Just a word of caution. Reg E prohibits you requiring the loan customer from auto-debiting their loan payments from a deposit account.
Specifically, the Commentary to Section 205.10(e)(1) states:
Loan payments. Creditors may not require repayment of loans by electronic means on a preauthorized, recurring basis. A creditor may offer a program with a reduced annual percentage rate or other cost-related incentive for an automatic repayment feature, provided the program with the automatic payment feature is not the only loan program offered by the creditor for the type of credit involved.