The Payoff Amount and Per Diem Amount quoted herein are effective through December 31, 2020. By including a per diem amount in the letter, the parties will not have to execute another payoff letter if the termination date.A 10 day payoff is crucial to getting your old loans paid off during a refinance. Learn how it works from start to finish. Please include a per diem amount in the statement. Please email this information to as soon as possible. The statement includes information and formulas to calculate on a per diem basis the payoff amount after the date it is issued. It typically details the principal balance, interest due as of that date, per diem, any late fees, etc.