Exclude an amount from the total, but add it to 1st payment. We have our own area - with 2 options. Cash / Check / Zelle is option 1 Creditcard / Paypal / Venmo is option 2. If they choose option 2 that amount should be added to the 1st payment (be outside of the computation of payments). example $1000 contract, $45 convenience fee, 80% do at job start. so $800 + $45 (not 80% of $1045).