(a) If a retail installment contract is amended to defer all or a part of one or more installments for not longer than three months, the holder may collect from the retail buyer:
(1) an amount computed on the amount deferred for the period of deferment at a rate that does not exceed the effective return for time price differential permitted for a monthly payment retail installment contract; and
(2) the amount of the additional cost to the holder for:
(A) premiums for continuing in force any insurance coverages provided for by the contract; and
(B) any additional necessary official fees.
(b) The minimum charge under Subsection (a)(1) is $1.