Texas Finance Code - FIN § 347.155. Prepayment

(a) A consumer may prepay in full the unpaid balance of a credit transaction at any time before maturity.

(b) On prepayment, after deduction of an acquisition charge that does not exceed $50, the consumer is entitled to a refund credit of the time price differential or interest.  The amount of the credit is computed on an actuarial basis in accordance with regulations of the Office of the Comptroller of the Currency adopted under the Depository Institutions Deregulation and Monetary Control Act of 1980 (12 U.S.C. Section 1735f-7a et seq.) for the prepayment of a mortgage loan that is secured by a first lien on a residential manufactured home.

(c) In making the computation under Subsection (b), the creditor may assume that payments on the credit transaction have been made as originally scheduled, ignoring any difference created by a late or early payment.