diff --git a/php/chronotrack_api/fx_chronotrack_admin.php b/php/chronotrack_api/fx_chronotrack_admin.php
index e1b241a..ae5a040 100644
--- a/php/chronotrack_api/fx_chronotrack_admin.php
+++ b/php/chronotrack_api/fx_chronotrack_admin.php
@@ -101,18 +101,37 @@ function fxChronotrackApiAdminRenderEventPage($intEveId, $strLangue = 'fr', $bln
         fxChronotrackApiAdminRenderEventLinkPicker($blnClosed);
     }
 
-    if ($arrConfig !== null) {
-        fxChronotrackApiAdminRenderStatusActions($intEveId, $strStatus, $blnEventLinked);
-    }
-
-    if ($arrConfig !== null) {
-        fxChronotrackApiAdminRenderRaceMapping($intEveId, $arrConfig, $strLangue, $blnClosed, $blnEventLinked);
-    }
-
+    // Sync d’abord (usage courant) ; config repliable ensuite. MSIN-4328
     if ($arrConfig !== null && $blnEventLinked && $blnConfigured) {
         fxChronotrackApiAdminRenderPushPanel($intEveId, $blnClosed);
     }
 
+    if ($arrConfig !== null && $blnEventLinked) {
+        $blnHasSavedMapping = false;
+        $arrMapRows = fxChronotrackApiRaceMapGetForEvent($intEveId);
+        foreach ($arrMapRows as $arrMapRow) {
+            if (intval($arrMapRow['ct_race_id'] ?? 0) > 0) {
+                $blnHasSavedMapping = true;
+                break;
+            }
+        }
+        $strConfigExpanded = $blnHasSavedMapping ? '' : ' show';
+        echo '<div class="card mb-4" id="ct_api_config_card">';
+        echo '<div class="card-header py-2">';
+        echo '<a class="d-block text-dark' . ($blnHasSavedMapping ? ' collapsed' : '') . '" data-toggle="collapse" '
+            . 'href="#ct_api_config_collapse" role="button" aria-expanded="'
+            . ($blnHasSavedMapping ? 'false' : 'true') . '">';
+        echo 'Configuration <span class="text-muted small">(cycle de vie, mapping épreuves)</span>';
+        echo '</a></div>';
+        echo '<div class="collapse' . $strConfigExpanded . '" id="ct_api_config_collapse"><div class="card-body pt-3">';
+        fxChronotrackApiAdminRenderStatusActions($intEveId, $strStatus, $blnEventLinked);
+        fxChronotrackApiAdminRenderRaceMapping($intEveId, $arrConfig, $strLangue, $blnClosed, $blnEventLinked);
+        echo '</div></div></div>';
+    } elseif ($arrConfig !== null) {
+        fxChronotrackApiAdminRenderStatusActions($intEveId, $strStatus, $blnEventLinked);
+        fxChronotrackApiAdminRenderRaceMapping($intEveId, $arrConfig, $strLangue, $blnClosed, $blnEventLinked);
+    }
+
     if ($blnEventLinked && $blnConfigured) {
         fxChronotrackApiAdminRenderDiagnosticPanel(intval($arrConfig['ct_event_id']));
     }
@@ -127,9 +146,9 @@ function fxChronotrackApiAdminRenderEventPage($intEveId, $strLangue = 'fr', $bln
 }
 
 function fxChronotrackApiAdminRenderStatusActions($intEveId, $strStatus, $blnEventLinked = true) {
-    $strStep = $blnEventLinked ? '1' : '2';
-    echo '<div class="card mb-4"><div class="card-header">' . $strStep . '. Cycle de vie sync</div><div class="card-body">';
-    echo '<p class="small text-muted">Activer avant la course ; <strong>Terminer</strong> après la course pour bloquer la sync auto et les changements de config.</p>';
+    echo '<div class="card mb-3 border"><div class="card-header py-2">Cycle de vie sync</div><div class="card-body py-3">';
+    echo '<p class="small text-muted mb-2">Activer avant la course ; <strong>Terminer</strong> après pour bloquer la sync auto '
+        . 'et les changements de config. (La sync auto différentielle viendra ensuite.)</p>';
     echo '<div class="btn-group" role="group">';
     if ($strStatus === MSIN_API_CHRONOTRACK_SYNC_LIE) {
         echo '<button type="button" class="btn btn-warning btn-sm ct-api-set-status" data-status="' . MSIN_API_CHRONOTRACK_SYNC_ACTIF . '">Activer la sync</button>';
@@ -160,8 +179,7 @@ function fxChronotrackApiAdminRenderRaceMapping($intEveId, $arrConfig, $strLangu
         }
     }
 
-    $strStep = $blnEventLinked ? '2' : '3';
-    echo '<div class="card mb-4"><div class="card-header">' . $strStep . '. Mapping épreuves MS1 → races ChronoTrack</div><div class="card-body">';
+    echo '<div class="card mb-0 border"><div class="card-header py-2">Mapping épreuves MS1 → races ChronoTrack</div><div class="card-body py-3">';
     if ($arrEpreuves === null || count($arrEpreuves) === 0) {
         echo '<p class="text-muted mb-0">Aucune épreuve MS1 pour cet événement.</p></div></div>';
         return;
@@ -227,26 +245,23 @@ function fxChronotrackApiAdminRenderRaceMapping($intEveId, $arrConfig, $strLangu
 }
 
 function fxChronotrackApiAdminRenderPushPanel($intEveId, $blnClosed = false) {
-    global $vDomaine;
     echo '<div class="card mb-4 border-primary" id="ct_api_push_card">';
-    echo '<div class="card-header">3. Synchronisation manuelle (participants)</div>';
+    echo '<div class="card-header">Synchronisation manuelle (participants)</div>';
     echo '<div class="card-body">';
     if ($blnClosed) {
         echo '<div class="alert alert-warning py-2 small mb-2">Événement fermé — push manuel autorisé pour tests ou rattrapage.</div>';
     }
-    echo '<p class="small text-muted mb-2">Push manuel · External ID = <code>par_id_original</code> · Pas de sync auto.</p>';
+    echo '<p class="small text-muted mb-2">Push <strong>différentiel</strong> MS1 → ChronoTrack '
+        . '(nouveaux / modifiés depuis le dernier push OK). External ID = <code>par_id_original</code>.</p>';
     echo '<div id="ct_api_push_summary" class="mb-2 text-muted small">Cliquez <strong>Actualiser</strong>.</div>';
     echo '<div id="ct_api_push_blocked_wrap" class="mb-2 d-none"></div>';
-    echo '<div id="ct_api_push_orphans_wrap" class="mb-2 d-none"></div>';
     echo '<div class="mb-2">';
     echo '<button type="button" class="btn btn-primary btn-sm" id="ct_api_btn_push" disabled>';
-    echo '<i class="fa fa-cloud-upload" aria-hidden="true"></i>&nbsp;Pousser</button> ';
+    echo '<i class="fa fa-cloud-upload" aria-hidden="true"></i>&nbsp;Pousser le différentiel</button> ';
     echo '<button type="button" class="btn btn-outline-secondary btn-sm" id="ct_api_btn_push_refresh">';
     echo '<i class="fa fa-refresh" aria-hidden="true"></i>&nbsp;Actualiser</button> ';
-    echo '<button type="button" class="btn btn-outline-warning btn-sm" id="ct_api_btn_orphans" disabled>';
-    echo '<i class="fa fa-unlink" aria-hidden="true"></i>&nbsp;<span id="ct_api_orphans_btn_label">Orphelines CT</span></button> ';
-    echo '<button type="button" class="btn btn-outline-secondary btn-sm" id="ct_api_btn_probe_push">';
-    echo '<i class="fa fa-flask" aria-hidden="true"></i>&nbsp;Sonde</button>';
+    echo '<button type="button" class="btn btn-outline-info btn-sm" id="ct_api_btn_ct_count">';
+    echo '<i class="fa fa-calculator" aria-hidden="true"></i>&nbsp;Nb ChronoTrack Live</button>';
     echo '</div>';
     echo '<div id="ct_api_push_result" class="small mt-2"></div>';
     echo '</div></div>';
@@ -258,14 +273,15 @@ function fxChronotrackApiAdminRenderDiagnosticPanel($intCtEventId) {
     echo 'Diagnostic API ChronoTrack <span class="text-muted small">(support — event ID ' . intval($intCtEventId) . ')</span>';
     echo '</a></div>';
     echo '<div class="collapse" id="ct_api_diagnostic_collapse"><div class="card-body">';
-    echo '<p class="small text-muted mb-2">Utilise les credentials MS1 déjà configurés (OAuth en cache). ';
-    echo 'Sonde <code>event/{id}/race</code>, <code>entry</code> (5 premières inscriptions), ';
-    echo '<code>event</code> et <code>reg_choice</code>. Copie le rapport pour le développement.</p>';
+    echo '<p class="small text-muted mb-2">Outils de support (credentials MS1 / OAuth en cache). '
+        . 'Pas nécessaire pour une course en production.</p>';
     echo '<button type="button" class="btn btn-outline-dark btn-sm mb-2" id="ct_api_btn_diagnostic">';
     echo '<i class="fa fa-stethoscope" aria-hidden="true"></i>&nbsp;Lancer le diagnostic API</button> ';
+    echo '<button type="button" class="btn btn-outline-secondary btn-sm mb-2" id="ct_api_btn_probe_push">';
+    echo '<i class="fa fa-flask" aria-hidden="true"></i>&nbsp;Sonde (1 participant POST)</button> ';
     echo '<button type="button" class="btn btn-outline-secondary btn-sm mb-2 d-none" id="ct_api_btn_diagnostic_copy">';
     echo 'Copier le rapport</button>';
-    echo '<div id="ct_api_diagnostic_out" class="small text-muted">Cliquez sur « Lancer le diagnostic API ».</div>';
+    echo '<div id="ct_api_diagnostic_out" class="small text-muted">Cliquez sur « Lancer le diagnostic API » ou « Sonde ».</div>';
     echo '</div></div></div>';
 }
 
@@ -285,16 +301,14 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
     }
     ?>
 <style>
-#ct_api_push_blocked_wrap .ct-api-blocked-table,
-#ct_api_push_orphans_wrap .ct-api-orphan-table { font-size: 0.8rem; }
-#ct_api_push_blocked_wrap .ct-api-blocked-table th,
-#ct_api_push_orphans_wrap .ct-api-orphan-table th { white-space: nowrap; }
-#ct_api_push_blocked_wrap .ct-api-blocked-scroll,
-#ct_api_push_orphans_wrap .ct-api-orphan-scroll { max-height: 55vh; overflow: auto; }
+#ct_api_push_blocked_wrap .ct-api-blocked-table { font-size: 0.8rem; }
+#ct_api_push_blocked_wrap .ct-api-blocked-table th { white-space: nowrap; }
+#ct_api_push_blocked_wrap .ct-api-blocked-scroll { max-height: 55vh; overflow: auto; }
 #ct_api_push_summary .ct-api-dash-table { font-size: 0.85rem; margin-bottom: 0.5rem; }
 #ct_api_push_summary .ct-api-dash-table th { background: #f8f9fa; font-weight: 600; white-space: nowrap; }
 #ct_api_push_summary .ct-api-dash-table td.num { text-align: right; font-variant-numeric: tabular-nums; font-weight: 600; }
 #ct_api_push_summary .ct-api-dash-push { font-size: 0.85rem; margin-bottom: 0; }
+#ct_api_config_collapse .card { box-shadow: none; }
 </style>
 <?php fxChronotrackApiAdminRenderLoaderAssets($vDomaine); ?>
 <script>
@@ -309,6 +323,7 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
     var blnInlineOnEventForm = <?php echo $blnInlineOnEventForm ? 'true' : 'false'; ?>;
     var xhrPushPreview = null;
     var blnPushPreviewLoaded = false;
+    var intCtLiveCount = null;
 
     function escHtml(str) {
         return String(str).replace(/&/g, '&amp;').replace(/</g, '&lt;').replace(/>/g, '&gt;');
@@ -684,6 +699,35 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
         window.prompt('Copier le rapport (Ctrl+C) :', strText);
     });
 
+    $('#ct_api_btn_probe_push').on('click', function () {
+        var $btn = $(this);
+        var $out = $('#ct_api_diagnostic_out');
+        $btn.prop('disabled', true);
+        $out.html(waitHtml('Sonde POST (1 participant)…'));
+        $('#ct_api_btn_diagnostic_copy').addClass('d-none');
+        $.post(strAjaxUrl, { a: 'sync_probe_push', eve_id: intEveId }, function (res) {
+            if (rejectIfSessionLost(res)) {
+                return;
+            }
+            var strClass = (res && res.state === 'ok') ? 'text-success' : 'text-danger';
+            var strHtml = '<div class="' + strClass + '"><strong>Sonde</strong> — '
+                + escHtml((res && res.message) ? res.message : 'Erreur') + '</div>';
+            if (res && res.payload) {
+                strHtml += '<pre class="small bg-light p-2 mt-2 mb-1" style="max-height:200px;overflow:auto;">'
+                    + escHtml(JSON.stringify(res.payload, null, 2)) + '</pre>';
+            }
+            if (res && res.response_body) {
+                strHtml += '<pre class="small bg-light p-2 mb-0" style="max-height:200px;overflow:auto;">'
+                    + escHtml(res.response_body) + '</pre>';
+            }
+            $out.html(strHtml);
+        }, 'json').fail(function () {
+            $out.html('<div class="text-danger">Erreur réseau (sonde).</div>');
+        }).always(function () {
+            $btn.prop('disabled', false);
+        });
+    });
+
     var objPushPreview = null;
 
     function renderBlockedPanel(res) {
@@ -754,59 +798,6 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
         $wrap.removeClass('d-none').html(html);
     }
 
-    function renderOrphansPanel(res) {
-        var $wrap = $('#ct_api_push_orphans_wrap');
-        if (!$wrap.length) {
-            return;
-        }
-        if (!res || res.state !== 'ok') {
-            $wrap.addClass('d-none').html('<div class="text-danger small">' + escHtml((res && res.message) ? res.message : 'Erreur') + '</div>');
-            return;
-        }
-        var tabRows = res.orphans || [];
-        if (!tabRows.length) {
-            $wrap.addClass('d-none').empty();
-            return;
-        }
-
-        var html = '<div class="card border-warning">';
-        html += '<div class="card-header py-2 bg-white d-flex justify-content-between align-items-center">';
-        html += '<strong class="text-warning small">Orphelines CT — ' + tabRows.length + '</strong>';
-        html += '<button type="button" class="btn btn-link btn-sm p-0" id="ct_api_btn_orphans_close">Fermer</button>';
-        html += '</div><div class="card-body py-2">';
-        html += '<div class="ct-api-orphan-scroll border rounded">';
-        html += '<table class="table table-sm table-striped ct-api-orphan-table mb-0">';
-        html += '<thead class="thead-light"><tr>';
-        html += '<th>Nom</th><th>external_id</th><th>Dossard</th><th>Statut</th><th>entry_id</th><th>Raison</th>';
-        html += '</tr></thead><tbody>';
-        $.each(tabRows, function (_, row) {
-            html += '<tr>';
-            html += '<td>' + escHtml(row.name || '—') + '</td>';
-            html += '<td>' + escHtml(row.external_id || '—') + '</td>';
-            html += '<td>' + escHtml(row.bib ? ('#' + row.bib) : '—') + '</td>';
-            html += '<td>' + escHtml(row.entry_status || '—') + '</td>';
-            html += '<td><code class="small">' + escHtml(row.entry_id || '') + '</code></td>';
-            html += '<td>' + escHtml(row.reason_label || row.reason || '') + '</td>';
-            html += '</tr>';
-        });
-        html += '</tbody></table></div></div></div>';
-        $wrap.removeClass('d-none').html(html);
-    }
-
-    function updateOrphansButton(intCount, intCtTotal, intLinked) {
-        var $btn = $('#ct_api_btn_orphans');
-        var $lbl = $('#ct_api_orphans_btn_label');
-        if (!$btn.length || !$lbl.length) {
-            return;
-        }
-        var strLabel = 'Orphelines CT';
-        if (intCount > 0) {
-            strLabel += ' (' + intCount + ')';
-        }
-        $lbl.text(strLabel);
-        $btn.prop('disabled', intCount <= 0 && intCtTotal <= intLinked);
-    }
-
     function renderPushPreview(res) {
         var $sum = $('#ct_api_push_summary');
         var $btn = $('#ct_api_btn_push');
@@ -817,8 +808,6 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
         if (!res || res.state !== 'ok') {
             $sum.html('<div class="text-danger">' + escHtml((res && res.message) ? res.message : 'Erreur') + '</div>');
             $('#ct_api_push_blocked_wrap').addClass('d-none').empty();
-            $('#ct_api_push_orphans_wrap').addClass('d-none').empty();
-            updateOrphansButton(0, 0, 0);
             $btn.prop('disabled', true);
             return;
         }
@@ -829,34 +818,34 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
             ? res.pending_push
             : (res.to_push || 0);
         var intMs1 = res.ms1_total || 0;
-        var intWillUpdate = res.will_update || res.already_in_ct || 0;
-        var intWillCreate = res.will_create || res.to_create || 0;
-        var intCtTotal = res.ct_total || 0;
-        var intOrphans = res.ct_orphans || 0;
         var blnFirst = !!res.is_first_push;
         var strLastPush = res.last_push_at || null;
 
         var html = '<table class="table table-sm table-bordered ct-api-dash-table mb-1">';
-        html += '<thead><tr><th></th><th class="text-right">Total</th><th class="text-right">Sync OK</th><th class="text-right">Hors sync</th></tr></thead>';
-        html += '<tbody>';
-        html += '<tr><td>MS1</td>';
+        html += '<thead><tr><th>MS1</th><th class="text-right">Total</th><th class="text-right">Éligibles</th>';
+        html += '<th class="text-right">Exclus</th><th class="text-right">Différentiel</th></tr></thead><tbody>';
+        html += '<tr><td>Participants</td>';
         html += '<td class="num">' + intMs1 + '</td>';
         html += '<td class="num text-primary">' + intEligible + '</td>';
-        html += '<td class="num text-danger">' + intBlocked + '</td></tr>';
-        html += '<tr><td>ChronoTrack</td>';
-        html += '<td class="num">' + intCtTotal + '</td>';
-        html += '<td class="num text-success">' + intWillUpdate + '</td>';
-        html += '<td class="num text-warning">' + intOrphans + '</td></tr>';
+        html += '<td class="num text-danger">' + intBlocked + '</td>';
+        html += '<td class="num ' + (intPending > 0 ? 'text-warning' : 'text-success') + '">' + intPending + '</td></tr>';
         html += '</tbody></table>';
 
-        // MSIN-4328 — ligne « à repousser » (par_maj > last_push_at)
+        if (intCtLiveCount !== null) {
+            html += '<p class="ct-api-dash-push mb-1 text-muted">ChronoTrack Live : <strong>'
+                + intCtLiveCount + '</strong> inscription(s) '
+                + '<button type="button" class="btn btn-link btn-sm p-0 align-baseline" id="ct_api_btn_ct_count_inline">recompter</button></p>';
+        } else {
+            html += '<p class="ct-api-dash-push mb-1 text-muted">ChronoTrack Live : total non chargé '
+                + '(bouton <em>Nb ChronoTrack Live</em> — optionnel).</p>';
+        }
+
         if (intPending > 0) {
             html += '<p class="ct-api-dash-push mb-1"><strong>À pousser :</strong> '
-                + intPending + (blnFirst ? ' (premier envoi)' : ' modifié(s) depuis le dernier push')
-                + ' · ' + intEligible + ' éligibles · ' + intWillCreate + ' créer · ' + intWillUpdate + ' maj CT</p>';
+                + intPending + (blnFirst ? ' (premier envoi / baseline)' : ' modifié(s) depuis le dernier push')
+                + '</p>';
         } else {
-            html += '<p class="ct-api-dash-push mb-1 text-success"><strong>À jour</strong> — '
-                + intEligible + ' éligibles, rien à repousser';
+            html += '<p class="ct-api-dash-push mb-1 text-success"><strong>À jour</strong> — rien à repousser';
             if (strLastPush) {
                 html += ' <span class="text-muted">(dernier push ' + escHtml(strLastPush) + ')</span>';
             }
@@ -865,8 +854,6 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
 
         $sum.html(html);
         renderBlockedPanel(res);
-        updateOrphansButton(intOrphans, intCtTotal, intWillUpdate);
-        $('#ct_api_push_orphans_wrap').addClass('d-none').empty();
         $btn.prop('disabled', intPending <= 0);
     }
 
@@ -903,12 +890,12 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
             }
             xhrPushPreview.abort();
         }
-        $sum.html(waitHtml('Calcul du diff MS1 ↔ ChronoTrack…'));
+        $sum.html(waitHtml('Lecture MS1 (éligibles / différentiel)…'));
         xhrPushPreview = $.ajax({
             url: strAjaxUrl,
             type: 'POST',
             dataType: 'json',
-            timeout: 180000,
+            timeout: 60000,
             data: { a: 'sync_preview', eve_id: intEveId }
         }).done(function (res) {
             if (rejectIfSessionLost(res)) {
@@ -921,7 +908,7 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
                 return;
             }
             var strMsg = (strStatus === 'timeout')
-                ? 'Délai dépassé — ChronoTrack met trop de temps à répondre. Réessayez avec Actualiser.'
+                ? 'Délai dépassé — réessayez Actualiser.'
                 : 'Erreur réseau (preview).';
             $sum.html('<div class="text-danger">' + escHtml(strMsg) + '</div>');
         }).always(function () {
@@ -929,6 +916,46 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
         });
     }
 
+    function loadCtLiveCount() {
+        var $btn = $('#ct_api_btn_ct_count');
+        var $sum = $('#ct_api_push_summary');
+        $btn.prop('disabled', true);
+        if ($sum.length && objPushPreview && objPushPreview.state === 'ok') {
+            // conserve le tableau MS1, indique le chargement CT
+            $sum.find('.ct-api-dash-push').first().replaceWith(
+                '<p class="ct-api-dash-push mb-1 text-muted">' + waitHtml('Comptage ChronoTrack Live…') + '</p>'
+            );
+        }
+        $.ajax({
+            url: strAjaxUrl,
+            type: 'POST',
+            dataType: 'json',
+            timeout: 180000,
+            data: { a: 'sync_ct_count', eve_id: intEveId }
+        }).done(function (res) {
+            if (rejectIfSessionLost(res)) {
+                return;
+            }
+            if (!res || res.state !== 'ok') {
+                window.alert((res && res.message) ? res.message : 'Impossible de compter sur ChronoTrack Live');
+                return;
+            }
+            intCtLiveCount = parseInt(res.ct_total, 10);
+            if (isNaN(intCtLiveCount)) {
+                intCtLiveCount = null;
+            }
+            if (objPushPreview && objPushPreview.state === 'ok') {
+                renderPushPreview(objPushPreview);
+            }
+        }).fail(function (jqXHR, strStatus) {
+            window.alert(strStatus === 'timeout'
+                ? 'Délai dépassé pour le comptage ChronoTrack Live.'
+                : 'Erreur réseau (comptage CT).');
+        }).always(function () {
+            $btn.prop('disabled', false);
+        });
+    }
+
     function maybeLoadPushPreviewOnReveal() {
         if (!$('#ct_api_push_card').length) {
             return;
@@ -948,66 +975,14 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
         $('#ct_api_btn_push_refresh').on('click', function () {
             loadPushPreview(true);
             $('#ct_api_push_result').empty();
-            $('#ct_api_push_orphans_wrap').addClass('d-none').empty();
         });
 
-        $('#ct_api_btn_orphans').on('click', function () {
-            var $btn = $(this);
-            var $wrap = $('#ct_api_push_orphans_wrap');
-            $btn.prop('disabled', true);
-            $wrap.removeClass('d-none').html(waitHtml('Chargement orphelines…'));
-            $.post(strAjaxUrl, { a: 'sync_orphans', eve_id: intEveId }, function (res) {
-                if (rejectIfSessionLost(res)) {
-                    return;
-                }
-                renderOrphansPanel(res);
-                if (res && res.state === 'ok') {
-                    updateOrphansButton(res.count || 0, res.ct_total || 0, res.linked_count || 0);
-                }
-            }, 'json').fail(function () {
-                $wrap.html('<div class="text-danger small">Erreur réseau.</div>');
-            }).always(function () {
-                if (objPushPreview && objPushPreview.state === 'ok') {
-                    updateOrphansButton(
-                        objPushPreview.ct_orphans || 0,
-                        objPushPreview.ct_total || 0,
-                        objPushPreview.already_in_ct || 0
-                    );
-                } else {
-                    $btn.prop('disabled', false);
-                }
-            });
+        $('#ct_api_btn_ct_count').on('click', function () {
+            loadCtLiveCount();
         });
-
-        $(document).on('click', '#ct_api_btn_orphans_close', function () {
-            $('#ct_api_push_orphans_wrap').addClass('d-none').empty();
-        });
-
-        $('#ct_api_btn_probe_push').on('click', function () {
-            var $btn = $(this);
-            var $res = $('#ct_api_push_result');
-            $btn.prop('disabled', true);
-            $res.html(waitHtml('Sonde POST (1 participant)…'));
-            $.post(strAjaxUrl, { a: 'sync_probe_push', eve_id: intEveId }, function (res) {
-                if (rejectIfSessionLost(res)) {
-                    return;
-                }
-                var strClass = (res && res.state === 'ok') ? 'text-success' : 'text-danger';
-                var strHtml = '<div class="' + strClass + '"><strong>Sonde</strong> — ' + escHtml((res && res.message) ? res.message : 'Erreur') + '</div>';
-                if (res && res.payload) {
-                    strHtml += '<pre class="small bg-light p-2 mt-2 mb-1" style="max-height:200px;overflow:auto;">'
-                        + escHtml(JSON.stringify(res.payload, null, 2)) + '</pre>';
-                }
-                if (res && res.response_body) {
-                    strHtml += '<pre class="small bg-light p-2 mb-0" style="max-height:200px;overflow:auto;">'
-                        + escHtml(res.response_body) + '</pre>';
-                }
-                $res.html(strHtml);
-            }, 'json').fail(function () {
-                $res.html('<div class="text-danger">Erreur réseau (sonde).</div>');
-            }).always(function () {
-                $btn.prop('disabled', false);
-            });
+        $(document).on('click', '#ct_api_btn_ct_count_inline', function (e) {
+            e.preventDefault();
+            loadCtLiveCount();
         });
 
         $('#ct_api_btn_push').on('click', function () {
@@ -1019,7 +994,7 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
                     intPending = objPushPreview.to_push || objPushPreview.transferable || 0;
                 }
             }
-            var strConfirm = 'Pousser ' + intPending + ' participant(s) vers ChronoTrack ?';
+            var strConfirm = 'Pousser le différentiel : ' + intPending + ' participant(s) vers ChronoTrack ?';
             if (!window.confirm(strConfirm)) {
                 return;
             }
@@ -1036,7 +1011,7 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
             var blnFatal = false;
 
             $btn.prop('disabled', true);
-            $('#ct_api_btn_push_refresh, #ct_api_btn_orphans, #ct_api_btn_probe_push').prop('disabled', true);
+            $('#ct_api_btn_push_refresh, #ct_api_btn_ct_count').prop('disabled', true);
 
             function renderProgress(intDone, intTot, strExtra) {
                 var intPct = (intTot > 0) ? Math.min(100, Math.round((intDone * 100) / intTot)) : 0;
@@ -1058,7 +1033,7 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
             }
 
             function finishPush() {
-                $('#ct_api_btn_push_refresh, #ct_api_btn_orphans, #ct_api_btn_probe_push').prop('disabled', false);
+                $('#ct_api_btn_push_refresh, #ct_api_btn_ct_count').prop('disabled', false);
                 $btn.prop('disabled', false);
                 var strFinal = (intErrSum === 0)
                     ? (intOkSum + ' participant(s) synchronisé(s) (POST ' + intPostSum + ' · PUT ' + intPutSum + ').')
@@ -1093,7 +1068,7 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
                     if (!res || (res.state !== 'ok' && res.state !== 'partial')) {
                         if (res && res.total === 0) {
                             renderPushResult(res);
-                            $('#ct_api_btn_push_refresh, #ct_api_btn_orphans, #ct_api_btn_probe_push').prop('disabled', false);
+                            $('#ct_api_btn_push_refresh, #ct_api_btn_ct_count').prop('disabled', false);
                             $btn.prop('disabled', false);
                             return;
                         }
@@ -1155,7 +1130,7 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
                 }
                 if (!prep || prep.state !== 'ok') {
                     renderPushResult(prep || { state: 'error', message: 'Préparation échouée' });
-                    $('#ct_api_btn_push_refresh, #ct_api_btn_orphans, #ct_api_btn_probe_push').prop('disabled', false);
+                    $('#ct_api_btn_push_refresh, #ct_api_btn_ct_count').prop('disabled', false);
                     $btn.prop('disabled', false);
                     return;
                 }
@@ -1173,7 +1148,7 @@ function fxChronotrackApiAdminRenderPageScript($intEveId, $arrConfig, $blnClosed
                 }
                 strMsg += '. Vérifiez que le code MSIN-4328 est déployé (action sync_push_prepare).';
                 renderPushResult({ state: 'error', message: strMsg });
-                $('#ct_api_btn_push_refresh, #ct_api_btn_orphans, #ct_api_btn_probe_push').prop('disabled', false);
+                $('#ct_api_btn_push_refresh, #ct_api_btn_ct_count').prop('disabled', false);
                 $btn.prop('disabled', false);
             });
         });
diff --git a/php/chronotrack_api/fx_chronotrack_sync.php b/php/chronotrack_api/fx_chronotrack_sync.php
index 05946ee..62d07b6 100644
--- a/php/chronotrack_api/fx_chronotrack_sync.php
+++ b/php/chronotrack_api/fx_chronotrack_sync.php
@@ -978,45 +978,9 @@ function fxChronotrackApiSyncBuildPreview($intEveId) {
 
     $intMs1Total = count($tabParticipants);
     $intTransferable = count($arrClass['transferable']);
-    $tabEligibleKeys = array();
-    foreach ($arrClass['transferable'] as $arrItem) {
-        $tabEligibleKeys[$arrItem['payload']['external_id']] = true;
-    }
-
-    $arrCtFetch = fxChronotrackApiSyncFetchCtEntriesIndexed($intCtEventId);
-    if ($arrCtFetch['state'] !== 'ok') {
-        return array(
-            'state'   => 'error',
-            'message' => $arrCtFetch['message'],
-        );
-    }
-
-    $tabCtEntries = $arrCtFetch['entries'];
-    $intCtTotal = intval($arrCtFetch['total_entry_count'] ?? count($tabCtEntries));
-    $intCtWithoutExt = intval($arrCtFetch['without_external_id'] ?? 0);
-    $intAlreadyInCt = 0;
-    $intToCreate = 0;
-
-    foreach ($tabEligibleKeys as $strExt => $blnTrue) {
-        if (isset($tabCtEntries[$strExt])) {
-            $intAlreadyInCt++;
-        } else {
-            $intToCreate++;
-        }
-    }
-
-    $intCtOrphans = 0;
-    if (!empty($arrCtFetch['entities']) && is_array($arrCtFetch['entities'])) {
-        $tabOrphanRows = fxChronotrackApiSyncComputeCtOrphanRows($arrCtFetch['entities'], $tabEligibleKeys);
-        $intCtOrphans = count($tabOrphanRows);
-    } else {
-        foreach ($tabCtEntries as $strExt => $blnEntity) {
-            if (!isset($tabEligibleKeys[$strExt])) {
-                $intCtOrphans++;
-            }
-        }
-    }
 
+    // MSIN-4328 — preview MS1 seul (rapide). Plus de scan CT fiche-par-fiche :
+    // le push upsert crée/maj sans avoir besoin du inventaire Live ici.
     $strLastPushAt = trim((string)($arrConfig['last_push_at'] ?? ''));
     $tabPending = fxChronotrackApiSyncFilterChangedSincePush($arrClass['transferable'], $strLastPushAt);
     $intPendingPush = count($tabPending);
@@ -1041,13 +1005,14 @@ function fxChronotrackApiSyncBuildPreview($intEveId) {
         'anomaly_duplicate_bib'  => $arrClass['blocked_duplicate_bib'],
         'duplicate_bib_numbers'  => $arrClass['duplicate_bib_numbers'],
         'anomalies'              => $arrClass['blocked'],
-        'ct_total'               => $intCtTotal,
-        'already_in_ct'          => $intAlreadyInCt,
-        'will_update'            => $intAlreadyInCt,
-        'to_create'              => $intToCreate,
-        'will_create'            => $intToCreate,
-        'ct_orphans'             => $intCtOrphans,
-        'ct_without_external_id' => $intCtWithoutExt,
+        'ct_total'               => null,
+        'ct_total_loaded'        => false,
+        'already_in_ct'          => null,
+        'will_update'            => null,
+        'to_create'              => null,
+        'will_create'            => null,
+        'ct_orphans'             => null,
+        'ct_without_external_id' => null,
         'to_push'                => $intPendingPush,
         'pending_push'           => $intPendingPush,
         'last_push_at'           => ($strLastPushAt !== '' && $strLastPushAt !== '0000-00-00 00:00:00')
@@ -1058,6 +1023,101 @@ function fxChronotrackApiSyncBuildPreview($intEveId) {
     );
 }
 
+/**
+ * MSIN-4328 — total entries CT Live (sans construire le diff MS1↔CT).
+ * Essaie d’abord un total dans la réponse API ; sinon compte par pagination légère.
+ */
+function fxChronotrackApiSyncExtractCtListTotal($mixJson) {
+    if (!is_array($mixJson)) {
+        return null;
+    }
+    $tabKeys = array(
+        'total', 'total_count', 'totalCount', 'count', 'entry_count', 'num_results',
+        'results_count', 'nb_results', 'total_entries',
+    );
+    foreach ($tabKeys as $strKey) {
+        if (isset($mixJson[$strKey]) && is_numeric($mixJson[$strKey])) {
+            $intVal = intval($mixJson[$strKey]);
+            if ($intVal >= 0) {
+                return $intVal;
+            }
+        }
+    }
+    foreach (array('pagination', 'page', 'meta', 'paging') as $strNest) {
+        if (!isset($mixJson[$strNest]) || !is_array($mixJson[$strNest])) {
+            continue;
+        }
+        $intNested = fxChronotrackApiSyncExtractCtListTotal($mixJson[$strNest]);
+        if ($intNested !== null) {
+            return $intNested;
+        }
+    }
+    return null;
+}
+
+function fxChronotrackApiSyncFetchCtEntryCount($intCtEventId) {
+    $intCtEventId = intval($intCtEventId);
+    if ($intCtEventId <= 0) {
+        return array('state' => 'error', 'message' => 'ct_event_id manquant', 'ct_total' => null);
+    }
+
+    // 1) Une page minimale — si CT renvoie un total, on s’arrête là.
+    $arrApi = fxChronotrackApiOAuthApiGet('event/' . $intCtEventId . '/entry', array(
+        'page'      => 1,
+        'page_size' => 1,
+    ));
+    if ($arrApi['state'] !== 'ok') {
+        return array(
+            'state'    => 'error',
+            'message'  => $arrApi['message'] ?? 'Erreur lecture entries CT',
+            'ct_total' => null,
+        );
+    }
+
+    $intFromMeta = fxChronotrackApiSyncExtractCtListTotal($arrApi['json'] ?? null);
+    if ($intFromMeta !== null) {
+        return array(
+            'state'      => 'ok',
+            'message'    => 'Total ChronoTrack Live (métadonnée API)',
+            'ct_total'   => $intFromMeta,
+            'via'        => 'meta',
+        );
+    }
+
+    // 2) Sinon compte page par page (gros page_size, on ne garde que le count).
+    $intTotal = 0;
+    $intPage = 1;
+    $intPageSize = 250;
+    $intMaxPages = 200;
+    while ($intPage <= $intMaxPages) {
+        $arrPage = fxChronotrackApiOAuthApiGet('event/' . $intCtEventId . '/entry', array(
+            'page'      => $intPage,
+            'page_size' => $intPageSize,
+        ));
+        if ($arrPage['state'] !== 'ok') {
+            return array(
+                'state'    => 'error',
+                'message'  => $arrPage['message'] ?? 'Erreur lecture entries CT',
+                'ct_total' => ($intTotal > 0) ? $intTotal : null,
+            );
+        }
+        $arrEntities = fxChronotrackApiNormalizeEntityList($arrPage['json'], 'entry');
+        $intN = count($arrEntities);
+        $intTotal += $intN;
+        if ($intN < $intPageSize) {
+            break;
+        }
+        $intPage++;
+    }
+
+    return array(
+        'state'    => 'ok',
+        'message'  => 'Total ChronoTrack Live (comptage paginé)',
+        'ct_total' => $intTotal,
+        'via'      => 'pages',
+    );
+}
+
 /**
  * Stockage job push (fichier temp) — évite de saturer $_SESSION sur ~2000 entries. MSIN-4328
  */
@@ -1149,20 +1209,11 @@ function fxChronotrackApiSyncPushPrepare($intEveId) {
     $strLastPushAt = trim((string)($arrConfig['last_push_at'] ?? ''));
     $tabPending = fxChronotrackApiSyncFilterChangedSincePush($arrClass['transferable'], $strLastPushAt);
 
-    $tabCtEntries = array();
-    $arrCtFetch = fxChronotrackApiSyncFetchCtEntriesIndexed($intCtEventId);
-    if ($arrCtFetch['state'] === 'ok') {
-        $tabCtEntries = $arrCtFetch['entries'];
-    }
-
+    // Plus de scan CT à la préparation : POST upsert (crée ou maj) sans entry_id.
     $tabBatch = array();
     $tabMeta = array();
     foreach ($tabPending as $arrItem) {
-        $arrPayload = fxChronotrackApiSyncEnrichPayloadWithCtEntry(
-            $arrItem['payload'],
-            $tabCtEntries[$arrItem['payload']['external_id']] ?? null
-        );
-        $tabBatch[] = $arrPayload;
+        $tabBatch[] = fxChronotrackApiSyncPayloadForPost($arrItem['payload']);
         $tabMeta[] = array(
             'par_id'      => intval($arrItem['row']['par_id'] ?? 0),
             'external_id' => $arrItem['payload']['external_id'],
diff --git a/superadm/ajax_chronotrack_api.php b/superadm/ajax_chronotrack_api.php
index cba39d2..521b8ac 100644
--- a/superadm/ajax_chronotrack_api.php
+++ b/superadm/ajax_chronotrack_api.php
@@ -91,10 +91,25 @@ switch ($strAction) {
             $tabRetour = array('state' => 'error', 'message' => 'eve_id manquant');
             break;
         }
-        set_time_limit(180);
+        set_time_limit(60);
         $tabRetour = fxChronotrackApiSyncBuildPreview($intEveId);
         break;
 
+    case 'sync_ct_count':
+        if ($intEveId <= 0) {
+            $tabRetour = array('state' => 'error', 'message' => 'eve_id manquant');
+            break;
+        }
+        $arrCfg = fxChronotrackApiConfigGet($intEveId);
+        $intCtEventId = intval($arrCfg['ct_event_id'] ?? 0);
+        if ($intCtEventId <= 0) {
+            $tabRetour = array('state' => 'error', 'message' => 'Événement non lié à ChronoTrack');
+            break;
+        }
+        set_time_limit(180);
+        $tabRetour = fxChronotrackApiSyncFetchCtEntryCount($intCtEventId);
+        break;
+
     case 'sync_probe_push':
         if ($intEveId <= 0) {
             $tabRetour = array('state' => 'error', 'message' => 'eve_id manquant');