7 C.F.R. § 3550.152 – Loan payments.

(a) Payment terms. Unless the loan documents specify other loan repayment terms, borrowers are required to make monthly payments. Borrowers with existing loans specifying annual payments may request conversion to monthly payments, and must convert to a monthly payment schedule before any subsequent loan or new payment assistance is approved. Suitable forms of payment are: check, money order, or bank draft. Borrowers who make cash payments will be assessed a fee to cover the cost of conversion to a money order.
(b) Application of payments. If a borrower makes less than the scheduled payment, the payment is held in suspense and is not applied to the borrower's account. When subsequent payments are received in an amount sufficient to equal a scheduled payment, the amount will be applied in the following order:
1. (1) Protective advances charged to the account.
2. (2) Accrued interest due.
3. (3) Principal due.
4. (4) Escrow for taxes and insurance.
(c) Multiple loans. When a borrower with multiple loans for the same property makes less than the scheduled payment on all loans, the payment will be applied to the oldest loan and then in declining order of age. Future remittances will be applied beginning with the oldest unpaid installment.
(d) Application of excess payments. Borrowers can elect to make payments in excess of the scheduled amount to be applied to principal, provided there are no outstanding fees.