(a) A holder of a retail installment contract, on request of the retail buyer, may agree to defer the scheduled due date of all or part of one or more installments.
(b) A holder may collect from the retail buyer for deferment of an installment:
(1) a charge that is a part of the time price differential and computed on the amount deferred for the period of deferment at the monthly rate of 15 cents for each $10; and
(2) the amount of the additional cost to the holder for:
(A) premiums for continuing in force any insurance provided for by the contract; and
(B) additional necessary official fees.
(c) The minimum charge under Subsection (b)(1) is $1.