Okay,
I have managed to sort my information and identify a pattern where I can decide if information is correctly input and incorrectly input. My problem is, I don't know how to put a formula into a pivot table which sorts the erronious entries properly.
This is what I am looking at:

Row Labels Sum of Quantity

519728 0
APENT 12
RCV -12

- The series above is incorrect as the sum of "519728" and "APENT" are not the same

477376 16
APENT 16
RCV 0

470336 6
APENT 6
RCV 0
-This series above is correct.

Ideally there would be a column to the left which said "error" and I could filter by that column. Could someone point me in the right direction? Thanks so much,
Aldek