diff --git a/modules/band-lineup/matching.js b/modules/band-lineup/matching.js
index cfea022..a12701d 100644
--- a/modules/band-lineup/matching.js
+++ b/modules/band-lineup/matching.js
@@ -128,7 +128,11 @@ function assignMembersToSlots(slots, members) {
       if (score > bestScore) { bestScore = score; bestIndex = i; }
     }
     if (bestIndex < 0) return null;
-    return pool.splice(bestIndex, 1)[0];
+    const chosen = pool.splice(bestIndex, 1)[0];
+    // One spot per person: someone scheduled twice (Leader + Acoustic) must not fill a second spot.
+    const key = chosen.personId || '';
+    if (key) for (let i = pool.length - 1; i >= 0; i -= 1) if (pool[i].personId === key) pool.splice(i, 1);
+    return chosen;
   });
 }
 
diff --git a/modules/band-lineup/matching.test.js b/modules/band-lineup/matching.test.js
index 516574c..90f30c8 100644
--- a/modules/band-lineup/matching.test.js
+++ b/modules/band-lineup/matching.test.js
@@ -65,3 +65,12 @@ console.log('assignment:', JSON.stringify(out));
   assert.strictEqual(bestLibraryMatch('Chris Smith', [{ id: '1', name: 'Chris' }, { id: '2', name: 'Chris' }]), null, 'ambiguous tie → null');
   console.log('bestLibraryMatch: all assertions passed ✓');
 }
+
+// --- one spot per person: someone scheduled twice (Leader + Acoustic) fills one spot only ---
+{
+  const P = (label, name, personId) => ({ label, name, personId });
+  const slots = ['[LEADER, VOX 1, ACOUSTIC] MIX 1', '[GUITAR, 2] MIX 7'];
+  const got = assignMembersToSlots(slots, [P('[Leader]', 'Mike', 'mp'), P('Guitar [Acoustic]', 'Mike', 'mp'), P('Guitar [Rhythm]', 'Craig', 'cs')]).map((m) => (m ? m.name : null));
+  assert.deepStrictEqual(got, ['Mike', 'Craig'], 'Mike once, Craig gets the guitar spot');
+  console.log('one spot per person: all assertions passed ✓');
+}
diff --git a/modules/band-lineup/server.js b/modules/band-lineup/server.js
index 92bcf63..abc1057 100644
--- a/modules/band-lineup/server.js
+++ b/modules/band-lineup/server.js
@@ -530,8 +530,8 @@ module.exports = {
         const openIdx = []; const manualNames = new Set();
         for (let i = 0; i < eff.length; i += 1) {
           const e = board[String(i)];
-          if (e && (e.personId || e.name) && e.plan === planId) {
-            const nm = e.personId ? (library[e.personId] && library[e.personId].name) : e.name;
+          if (e && (e.personId || e.name || e.pco) && e.plan === planId) {
+            const nm = e.pco ? e.pco.name : e.personId ? (library[e.personId] && library[e.personId].name) : e.name;
             if (nm) manualNames.add(normName(nm));
           } else openIdx.push(i);
         }
@@ -675,6 +675,10 @@ module.exports = {
         const from = String(p.get('from') || ''); const to = String(p.get('to') || '');
         if (!/^\d+$/.test(from) || !/^\d+$/.test(to) || from === to) return json(res, 400, { error: 'Bad move.' });
         const a = current.board[from]; const b = current.board[to];
+        // Moving a spot is a hand placement for this plan: Sync must not move it back.
+        const plan = current.planId();
+        if (a) a.plan = plan;
+        if (b) b.plan = plan;
         if (a === undefined) delete current.board[to]; else current.board[to] = a;
         if (b === undefined) delete current.board[from]; else current.board[from] = b;
         current.saveBoard(); current.rebuildLocal();