Sec. 1331. (a) An infrastructure agency shall, within the time described in the zone improvement plan, construct infrastructure for which:
(1) a zone improvement plan has been adopted;
(2) an impact zone has been established; and
(3) an impact fee has been collected.
(b) A unit may amend the unit's zone improvement plan, including the time provided in the plan for construction of infrastructure, only if the amount of expenditures provided for the construction of infrastructure in the original plan does not decrease in any year and the benefit to the overall impact zone does not decrease because of the amendment.