(a) The board shall:
(1) designate amounts as carryforward in accordance with the system of priority classifications specified in Sections 1372.063-1372.068; and
(2) in each classification, make the designations in order of the application for those designations.
(b) Notwithstanding Subsection (a), the board shall designate in compliance with the requirements of Section 146(f), Internal Revenue Code of 1986, a carryforward relating to an issuer's written election under Section 1372.042(c) according to the category of bonds to which the reservation subject to the carryforward relates.