Unless refunded, an excess payment would be a considered a "credit" for the customer.  It's even listed under unused credits in the contacts.  However, there appears to be no way to send the customer proof of credit (a credit note) for the specific excess payment, and my customer wanted to be sent one.

The only way (that I can see) that Books gives customers an indication that they may have credit for an excess payment is to send a copy of the receipt (proof of payment) with tiny text on the bottom that says, "over payment".  But this is just an indication.  Nowhere on the receipt does the customer see proof of credit.

And I could find no option when categorizing the excess payment under banking to create a credit note and associate a payment with one.

What I had to do was create a credit note manually, email it to the customer, and then delete it, because it then doubles the amount of credit that the customer has.

Am I missing something?