By including a per diem amount in the letter, the parties will not have to execute another payoff letter if the termination date. Searching for a fillable Mortgage Loan Payoff Letter Template?Use our easy editor for PDF files and fill this form out quickly. Add the interest, the principal balance. To start the process upload the completed Loan Payoff Notice Form into DMS along with the following documents. " The Borrower's written payoff request. Discover more about per diem interest—the daily interest on a loan that occurs outside of the standard repayment period. It typically details the principal balance, interest due as of that date, per diem, any late fees, etc. Select one loan in the main window and click Loan > Payoff Calculator on the main menu to open this window. A 10 day payoff is crucial to getting your old loans paid off during a refinance.