(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 Section 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.