If a mandated program included in the State Mandates Apportionment System is modified or amended by the Legislature or by executive order, and the modification or amendment significantly affects the costs of the program, as determined by the commission, the program shall be removed from the State Mandate Apportionment System, and the payments reduced accordingly. Local entities or school districts may submit actual costs claims for a period of three years, after which the program may be considered for inclusion in the State Mandates Apportionment System, pursuant to the provisions of Section 17615.4.