(a) The commission by rule may adopt a system under which licenses expire on various dates during the year.
(b) A license issued under a program governed by this subchapter may not expire later than the second anniversary of the date the license is issued.

(c) For the year in which the expiration date of a license is changed, the department shall prorate license fees on a monthly basis so that each license holder pays only that portion of the license fee that is allocable to the number of months during which the license is valid. On renewal of the license on the new expiration date, the total license renewal fee is payable.