Interesting your client chose this out of all the options, lol.

Agree with Susan someone would want to call the IRS.

The reason is that 965 installments are administered separately from regular tax liabilities.  With each installment received, the IRS would reconcile that against the taxpayer's outstanding 965 installment for prior years and the installment due for the current year.  Overpayment, if any, would then be applied or refunded.

If your client doesn't have any 965 liability, the payment erroneously designated for 965 should then be refunded if not for the balance due on the 2022 return.