Do not subtract a bank cost or reduce the commitment on that assumption. Use the instructed amount and clarify transaction mechanics before payment.
Budget the bank service separately
The individual route currently also has US$15,000 nonrefundable processing. A bank charge is not itself part of the government gift, and a technical limit does not establish a discounted program amount. Distinguish the amount instructed, the amount debited and the amount received, because in an international transfer these three figures are routinely different and only one of them satisfies anything.
Sending banks charge for the service, correspondent banks may deduct along the route, and a currency conversion applies whatever rate and spread the executing bank uses on the day. Hypothetical example: the full instructed figure is sent, a correspondent deducts its handling charge in transit, and the amount arriving is short by that deduction; the applicant has paid for a service, and the obligation has not been fully discharged. Ask the bank before sending whether charges will be borne by the sender so that the full amount arrives, and ask what the executing rate will be rather than reading a published mid-market rate.
Bank charges of any kind are the applicant's cost of moving money and are not part of what is paid to the U.S. government, and no banking constraint reduces a published programme amount.