(a) At the time the governing body of the municipality adopts an ordinance annexing an area for limited purposes, the governing body must also adopt by ordinance a regulatory plan for the area.
(b) The adopted regulatory plan must be the same as the regulatory plan prepared under § 43.123 unless the governing body finds and states in the ordinance the reasons for the adoption of a different regulatory plan.

(c) The governing body by ordinance may change a regulatory plan adopted under Subsection (b) if, in the ordinance making the change, the governing body finds and states the reasons for the adoption of the change.