diff --git a/AyCode.Core/Serializers/Binaries/AcBinarySerializer.BinarySerializationContext.cs b/AyCode.Core/Serializers/Binaries/AcBinarySerializer.BinarySerializationContext.cs
index 712df90..ee8c387 100644
--- a/AyCode.Core/Serializers/Binaries/AcBinarySerializer.BinarySerializationContext.cs
+++ b/AyCode.Core/Serializers/Binaries/AcBinarySerializer.BinarySerializationContext.cs
@@ -132,15 +132,14 @@ public static partial class AcBinarySerializer
 
         /// <summary>
         /// Sorts write plan by VisitIndex for sequential cursor consumption in write pass.
-        /// Called once after scan pass completes. Pre-loads first entry for TryConsumeWritePlanEntry.
+        /// Called once after scan pass completes.
         /// </summary>
         internal void SortWritePlan()
         {
             if (_writePlanCount > 1)
                 _writePlan.AsSpan(0, _writePlanCount).Sort(static (a, b) => a.VisitIndex.CompareTo(b.VisitIndex));
 
-            if (_writePlanCount > 0)
-                _nextWritePlanEntry = _writePlan![0];
+            _nextWritePlanVisitIndex = _writePlanCount > 0 ? _writePlan![0].VisitIndex : int.MaxValue;
         }
 
         /// <summary>Write pass cursor index into sorted _writePlan array.</summary>
@@ -150,10 +149,9 @@ public static partial class AcBinarySerializer
         internal int WriteVisitIndex;
 
         /// <summary>
-        /// Pre-loaded next write plan entry. Null when plan is empty or exhausted.
-        /// Avoids array access on hit path — entry is already cached.
+        /// Pre-cached VisitIndex of the next write plan entry, or int.MaxValue when exhausted.
         /// </summary>
-        private WriteDuplicateEntry? _nextWritePlanEntry;
+        private int _nextWritePlanVisitIndex = int.MaxValue;
 
         /// <summary>
         /// Set per-property in WritePropertyOrSkip before calling WriteString.
@@ -171,13 +169,12 @@ public static partial class AcBinarySerializer
         internal bool TryConsumeWritePlanEntry(out WriteDuplicateEntry entry)
         {
             var visitIndex = WriteVisitIndex++;
-            var next = _nextWritePlanEntry;
-            if (next != null && visitIndex == next.Value.VisitIndex)
+            if (visitIndex == _nextWritePlanVisitIndex)
             {
-                entry = next.Value;
-                _nextWritePlanEntry = ++WritePlanCursor < _writePlanCount
-                    ? _writePlan![WritePlanCursor]
-                    : null;
+                entry = _writePlan![WritePlanCursor++];
+                _nextWritePlanVisitIndex = WritePlanCursor < _writePlanCount
+                    ? _writePlan[WritePlanCursor].VisitIndex
+                    : int.MaxValue;
                 return true;
             }
             entry = default;
@@ -300,7 +297,7 @@ public static partial class AcBinarySerializer
             ScanVisitIndex = 0;
             WritePlanCursor = 0;
             WriteVisitIndex = 0;
-            _nextWritePlanEntry = null;
+            _nextWritePlanVisitIndex = int.MaxValue;
             StringInternEligible = false;
 
             // Clear write plan string references to avoid GC pinning, keep array if small enough