D.C. Mun. Regs. tit. 16, r. 16-337
Notwithstanding the provisions of any instrument of security or refinancing contract to the contrary, any buyer may, at any time before maturity, prepay the balance due under that instrument or contract in full in cash or, with the approval of the holder, by extension, renewal, or otherwise.
If any buyer prepays the balance due under an instrument of security or a refinancing contract, as provided in this section, the buyer shall be entitled to receive a refund of finance charges computed according to the actuarial method, as described by the federal Truth in Lending Act (82 Stat. 149; 15 U.S.C. § 1606(a)(1)(A); 5-29-68) and the regulations issued under that Act.
If any charge is included in a retail installment contract for credit life insurance, and that retail installment contract is prepaid in full prior to maturity, the holder shall refund or cause to be refunded to the buyer a portion of the credit life insurance charge which shall be not less than an amount computed under the formula commonly referred to as the "actuarial rebate formula" as soon as the buyer does either of the following:
No refund shall be required in any case under § 337.3 which, when computed by the actuarial rebate formula, would be less than one dollar ($ 1).
D.C. Mun. Regs. tit. 16, r. 16-337