(a) The board may designate as carryforward:
(1) the amount of the state ceiling that is not reserved before December 15; and
(2) any amount of the state ceiling that:
(A) was reserved before December 15; and
(B) becomes available on or after that date because of the cancellation of a reservation.
(b) The board shall designate as carryforward:
(1) a reservation amount for which the board receives written notice from an issuer of an election to carry forward the reservation under § 1372.042(c) if the bonds relating to the reservation are not required to close by December 31 of the year in which the reservation was granted; or
(2) an amount previously designated as carryforward under Subsection (a) for which the board receives written notice from an issuer of an election to reassign the carryforward designation under § 1372.074.