Hi, Linda-
Why not include the "paid in full" transactions? For a given customer
if you consider all the charges and all the payments, the paid-in-
fulls will simply "wash" (net to a zero sum), and the difference
between total charges and total payments is the amount outstanding. I
think you'll be doing yourself a favor to include all transactions.
And if you ever need to create a statement type of report, you'll have
the data on hand already.

Just another $0.02~

DaveO
Eschew obfuscation