Agreed. Your institution just made an interest-free loan. APR and FC accuracy is the central theme of the Truth in Lending Act, which officially made it a law for creditors to honor what they disclosed. That final disclosure is binding, and if the loan has closed, there is no way to re-disclose your way out of it. Doing so is tantamount to the creditor going back on its word.
The result: The APR stated on the TILA disclosure is what the borrower gets. If you charge more than that, you are in violation of TILA, subject to civil liability (the customer can sue you for actual damages - all finance charges and fees - and legal fees) and administrative liability (examiners making you give restitution, and citing you for the violation).
It does not matter if it was an inadvertent error. The CFPB sums it up most succinctly: "The TILA authorizes federal regulatory agencies to require financial institutions to make monetary and other adjustments to the consumers’ accounts when the true finance charge or APR exceeds the disclosed finance charge or APR by more than a specified accuracy tolerance.
That authorization extends to unintentional errors, including isolated violations (e.g., an error that occurred only once or errors, often without a common cause, that occurred infrequently and randomly). CFPB Manual - see page 140Your only choice is to make reality match the disclosure.
I am giving a presentation on "Reimbursements for Reg Z Violations" at next week's BOL Lending Triage. I'll go over this matter in depth!
2022 BOL Triage agenda