All prepayments shall first be applied to outstanding late fees, then to accrued interest and thereafter to the principal loan amount. Here's the information you'll need to have handy to complete your secured promissory note, installment with balloon final payment.A Promissory Note with Balloon Payments is a loan contract that enables a lender set loan terms with one or more larger payments at the end. A balloon payment is a larger than current one time payment at the close of the loan term. A balloon payment clause refers to a provision in a loan agreement that requires the borrower to make one large payment at the end of the loan term.