(a) A revolving credit account that provides for equal billing cycles may provide for interest for a billing cycle at the rate equal to one-twelfth of the applicable annual interest rate on the average daily balance of the account during that billing cycle.
(b) In any 12-month period, billing cycles are considered to be equal if:
(1) the number of billing cycles in the period does not exceed 12; and
(2) the difference between the length of the longest and the shortest billing cycles in the period does not exceed eight days.
Official text of the Texas Finance Code as published by the Texas Legislative Council.