(a) Except as provided by Subchapter B, a person may contract for, charge, or receive a rate or amount that does not exceed the applicable interest rate ceiling provided by this chapter. The use of a ceiling provided by this chapter for any contract is optional, and a contract may provide for a rate or amount allowed by other applicable law.
(b) A contract that is subject to Chapter 342, 345, 347, 348, or 353, including a contract for an open-end account, may, as an alternative to an interest rate or amount of time price differential allowed under that chapter, provide for a simple or precomputed rate or amount of time price differential that does not exceed the applicable ceiling provided by this chapter or by the equivalent yield authorized by Chapter 342, 345, 347, 348, or 353.
(c) Except as inconsistent with this chapter, a party to a contract that is subject to Chapter 342, 345, 347, 348, or 353, or the party's assignee, has all rights, duties, and obligations under the applicable chapter, including those relating to refund credits on prepayment or acceleration.