ExistingExpirationDateAndQty Function

the function in object, present in codeunit 6500, there's a major threat in performance, if you use the tracking module. Here's the old code (with a lot of data, a single reclassification journal line could post in 20-30 seconds O.o)

IF ItemLedgEntry.FINDSET THEN
  REPEAT
    SumOfEntries += ItemLedgEntry."Remaining Quantity";
  UNTIL ItemLedgEntry.NEXT = 0;

here's how i modified it:

ItemLedgEntry.CALCSUMS("Remaining Quantity");
  SumOfEntries := ItemLedgEntry."Remaining Quantity";
//IF ItemLedgEntry.FINDSET THEN
  //REPEAT
  //  SumOfEntries += ItemLedgEntry."Remaining Quantity";
  //UNTIL ItemLedgEntry.NEXT = 0;

I'm wondering why it wasn't done in "my" way...any idea? Am I missing something, maybe?