diff --git a/code/locus.c b/code/locus.c
index d4fb3a86c6..aaf3ac81ab 100644
--- a/code/locus.c
+++ b/code/locus.c
@@ -652,13 +652,16 @@ Res PoolGenAlloc(Seg *segReturn, PoolGen pgen, SegClass klass, Size size,
  * <design/strategy#.accounting.op.fill>
  */
 
-void PoolGenAccountForFill(PoolGen pgen, Size size)
+void PoolGenAccountForFill(PoolGen pgen, Size size, Bool deferred)
 {
   AVERT(PoolGen, pgen);
 
   AVER(pgen->freeSize >= size);
   pgen->freeSize -= size;
-  pgen->bufferedSize += size;
+  if (deferred)
+    pgen->newDeferredSize += size;
+  else
+    pgen->newSize += size;
 }
 
 
@@ -676,13 +679,13 @@ void PoolGenAccountForEmpty(PoolGen pgen, Size used, Size unused, Bool deferred)
 {
   AVERT(PoolGen, pgen);
   AVERT(Bool, deferred);
+  
+  UNUSED(used);
 
-  AVER(pgen->bufferedSize >= used + unused);
-  pgen->bufferedSize -= used + unused;
   if (deferred) {
-    pgen->newDeferredSize += used;
+    pgen->newDeferredSize -= unused;
   } else {
-    pgen->newSize += used;
+    pgen->newSize -= unused;
   }
   pgen->freeSize += unused;
 }
@@ -704,15 +707,13 @@ void PoolGenAccountForAge(PoolGen pgen, Size wasBuffered, Size wasNew,
   AVERT(PoolGen, pgen);
   AVERT(Bool, deferred);
 
-  AVER(pgen->bufferedSize >= wasBuffered);
-  pgen->bufferedSize -= wasBuffered;
   if (deferred) {
     AVER(pgen->newDeferredSize >= wasNew);
-    pgen->newDeferredSize -= wasNew;
+    pgen->newDeferredSize -= wasNew + wasBuffered;
     pgen->oldDeferredSize += wasBuffered + wasNew;
   } else {
     AVER(pgen->newSize >= wasNew);
-    pgen->newSize -= wasNew;
+    pgen->newSize -= wasNew + wasBuffered;
     pgen->oldSize += wasBuffered + wasNew;
   }
 }
diff --git a/code/locus.h b/code/locus.h
index 10867596d7..1ab41eb206 100644
--- a/code/locus.h
+++ b/code/locus.h
@@ -116,7 +116,7 @@ extern Res PoolGenAlloc(Seg *segReturn, PoolGen pgen, SegClass klass,
                         Size size, ArgList args);
 extern void PoolGenFree(PoolGen pgen, Seg seg, Size freeSize, Size oldSize,
                         Size newSize, Bool deferred);
-extern void PoolGenAccountForFill(PoolGen pgen, Size size);
+extern void PoolGenAccountForFill(PoolGen pgen, Size size, Bool deferred);
 extern void PoolGenAccountForEmpty(PoolGen pgen, Size used, Size unused, Bool deferred);
 extern void PoolGenAccountForAge(PoolGen pgen, Size wasBuffered, Size wasNew, Bool deferred);
 extern void PoolGenAccountForReclaim(PoolGen pgen, Size reclaimed, Bool deferred);
diff --git a/code/poolamc.c b/code/poolamc.c
index c526c8e56f..f07d67a80d 100644
--- a/code/poolamc.c
+++ b/code/poolamc.c
@@ -990,7 +990,7 @@ static Res AMCBufferFill(Addr *baseReturn, Addr *limitReturn,
     }
   }
 
-  PoolGenAccountForFill(pgen, SegSize(seg));
+  PoolGenAccountForFill(pgen, SegSize(seg), MustBeA(amcSeg, seg)->deferred);
   MustBeA(amcSeg, seg)->accountedAsBuffered = TRUE;
 
   *baseReturn = base;
diff --git a/code/poolams.c b/code/poolams.c
index a76c5a86d8..1762632a69 100644
--- a/code/poolams.c
+++ b/code/poolams.c
@@ -939,7 +939,7 @@ static Bool amsSegBufferFill(Addr *baseReturn, Addr *limitReturn,
   segBase = SegBase(seg);
   base = PoolAddrOfIndex(segBase, pool, baseIndex);
   limit = PoolAddrOfIndex(segBase, pool, limitIndex);
-  PoolGenAccountForFill(PoolSegPoolGen(pool, seg), AddrOffset(base, limit));
+  PoolGenAccountForFill(PoolSegPoolGen(pool, seg), AddrOffset(base, limit), FALSE);
   DebugPoolFreeCheck(pool, base, limit);
 
   *baseReturn = base;
diff --git a/code/poolawl.c b/code/poolawl.c
index 17347d7af5..34f689b4f1 100644
--- a/code/poolawl.c
+++ b/code/poolawl.c
@@ -500,7 +500,7 @@ static Bool awlSegBufferFill(Addr *baseReturn, Addr *limitReturn,
   segBase = SegBase(seg);
   base = PoolAddrOfIndex(segBase, pool, baseIndex);
   limit = PoolAddrOfIndex(segBase, pool, limitIndex);
-  PoolGenAccountForFill(PoolSegPoolGen(pool, seg), AddrOffset(base, limit));
+  PoolGenAccountForFill(PoolSegPoolGen(pool, seg), AddrOffset(base, limit), FALSE);
 
   *baseReturn = base;
   *limitReturn = limit;
diff --git a/code/poollo.c b/code/poollo.c
index 61311f049b..15c41f0c3b 100644
--- a/code/poollo.c
+++ b/code/poollo.c
@@ -250,7 +250,7 @@ static Bool loSegBufferFill(Addr *baseReturn, Addr *limitReturn,
   segBase = SegBase(seg);
   base = PoolAddrOfIndex(segBase, pool, baseIndex);
   limit = PoolAddrOfIndex(segBase, pool, limitIndex);
-  PoolGenAccountForFill(PoolSegPoolGen(pool, seg), AddrOffset(base, limit));
+  PoolGenAccountForFill(PoolSegPoolGen(pool, seg), AddrOffset(base, limit), FALSE);
 
   *baseReturn = base;
   *limitReturn = limit;