(A) In a city school district in a city having a population of one million or more inhabitants such contract shall also include a plan, which shall be developed in collaboration with the collective bargaining units representing teachers and the principals and signed off on by the chancellor and the presidents of each bargaining unit, to reduce actual class sizes,
beginning September two thousand twenty-two and to be achieved by September two thousand twenty-seven for all classes, with the exception of physical education and performing groups, as follows:
(1) kindergarten-third grade to have no more than twenty students per class;
(2) fourth-eighth grade to have no more than twenty-three students per class; and (3) high school to have no more than twenty-five students per class. Physical education and performing groups shall have no more than forty students per class at all levels. Each year of the plan, an additional twenty percent of the classrooms in the city school district, excluding special education classes, shall be in compliance with the class size targets such that the city school district is in full compliance by two thousand twenty-seven and all classes should maintain the target class size. The class size reduction plan shall prioritize schools serving populations with higher poverty levels.