D.C. Mun. Regs. tit. 16, r. 16-328
Public Law 86-431, § 2 (D.C. Official Code §§ 50-602 et seq.), regulates and controls the maximum finance charges allowable in connection with the sale of motor vehicles. [See Also: D.C. Official Code §§ 28-3601 et seq.].
The finance charge authorized by the preceding subsection shall be computed on the principal balance payable for a motor vehicle from the date of the instrument or contract until the maturity of the final installment, notwithstanding that the balance thereof is required to be paid in installments.
For a period less or greater than twelve (12) months or for amounts less or greater than one hundred dollars ($ 100), the amount of the maximum charge set forth in the foregoing schedule shall be decreased or increased proportionately.
D.C. Mun. Regs. tit. 16, r. 16-328