diff --git a/blueflood-core/src/main/java/com/rackspacecloud/blueflood/io/NumericSerializer.java b/blueflood-core/src/main/java/com/rackspacecloud/blueflood/io/NumericSerializer.java
index <HASH>..<HASH> 100644
--- a/blueflood-core/src/main/java/com/rackspacecloud/blueflood/io/NumericSerializer.java
+++ b/blueflood-core/src/main/java/com/rackspacecloud/blueflood/io/NumericSerializer.java
@@ -98,8 +98,7 @@ public class NumericSerializer {
     }
 
     private static void serializeRollup(BasicRollup basicRollup, byte[] buf) throws IOException {
-        // todo: simplify: rollupSize.update(buf.length); right?
-        rollupSize.update(sizeOf(basicRollup, Type.B_ROLLUP));
+        rollupSize.update(buf.length);
         CodedOutputStream protobufOut = CodedOutputStream.newInstance(buf);
         serializeRollup(basicRollup, protobufOut);
     }
keep track of the buffer size we serialize to rather than recompute the size of the rollup.