I had a customer who overpaid by 0.04 cents but i cant save the payment as a box comes up to say to allocate this payment. The only option i have is to take it off the next invoices BUT the following month when the same customer pays again the 0.04 cents still arises so in actualy fact the 0.04 cents will always be an issue.  Where as on your Tas accounts there was an option to put this 0.04 cent into an overpayment which meant it was dealt with at the time and didnt cause any issues.