Texas Finance Code Sec. § 303.002 Weekly Ceiling The parties to a written agreement may agree to an interest rate, or in an agreement described by Chapter 345 (Retail Installment Sales), 347 (Manufactured Home Credit Transactions), 348 (Motor Vehicle Installment Sales), or 353 (Commercial Motor Vehicle Installment Sales), an amount of time price differential producing a rate, that does not exceed the applicable weekly ceiling. Amended by Acts 1999, 76th Leg., ch. 62, Sec. 7.18(a), eff. Sept. 1, 1999. Amended by: Acts 2011, 82nd Leg., R.S., Ch. 117 (H.B. 2559), Sec. 3, eff. September 1, 2011.