It's the payoff amount 10 days in the future. A 10day payoff refers to the time it takes for your new lender to pay off your old loans during a refinance.A payoff letter provides instructions on how to pay off a loan with a lump sum before the loan term ends. Learn how payoff letters work. The first step is to get in touch with your lender or loan servicer. You can find their contact information on your monthly statements. Discover more about per diem interest—the daily interest on a loan that occurs outside of the standard repayment period. By including a per diem amount in the letter, the parties will not have to execute another payoff letter if the termination date. Your 10day payoff letter is crucial to ensuring that your new lender sends the correct amount of money so there is no outstanding loan balance left over. 366(2)(a)(10). Dept. Reg. 360-4.9. 10 NYCRR 415.26(h)(5). ADM.