520. The council of commissioners or the provisional council of the new school board shall draw up a staffing plan to determine the personnel requirements of the new school board for each class of employees who are members of a certified association within the meaning of the Labour Code (chapter C-27) and, in collaboration with other interested councils of commissioners or provisional councils, a transfer plan. The plans must be drawn up in accordance with the norms and modalities established pursuant to sections 512 to 518.