First - on the Aged AR report is there a positive and a negative? This means a payment or credit wasn't applied to an invoice.You can go through the AR transactions, find the transaction that wasn't applied and apply it.

If this is not the case, then I would suggest making a backup of the database. Then go to data verification and only check rebuild AR balance for single client and choose the client. After this finishes, see if the balances are now correct. If they are you are good to go. If not, restore the backup and you will need to work with support or a certified consultant to determine the issue.

Thank you, Caren. There wasn't a positive in addition to the negative on the AR report, so I made a backup and rebuilt the AR balance for the client. Now when I print an invoice it matches the negative balance on the AR report.

However, the negative balance does not equal (invoice total) minus (payment total) minus (credit total). No other transaction types were used. Could it be that the remainder is due to interest that shouldn't have been charged, had the invoices been calculated correctly?

To clarify, I'm talking about the invoice total, payment total, and credit total in the accounts receivable list ("show payments and receivables"), not on the invoice.

That doesn't change my response.

Thanks for your response - very helpful. I replied to it with an additional question, and then wanted to clarify that question.

Without eyes on  it is hard to say where the difference is from.  You might run a statement for the client to say the details.