We need to be able to refund specific amounts and/or just the tip on specific transactions. There have been several occurrences when, despite their best efforts, my employees have input too large of a tip amount. Example: a customer left a $4.00 tip, but they accidentally put $44.00. It was a total accident, but it went unnoticed until the next day after the credit sales had been closed out. Then, we could only refund the entire transaction or specific items. If we were able to refund just the tip or even the specific amount of $40.00 our problem could have easily been handled ourselves. I can understand not being able to charge a customer more after the fact, but not being able to give them money back seems a bit silly.
Therefore, my suggestion is to be able to refund a specific amount on a specific transaction, or to be able to refund just the tip on a specific transaction.