(a) Nothing in this subchapter shall be construed to remove or limit the powers of the cooperating cities and counties as provided by state law.
(b) All legislative power with respect to zoning and other planning legislation shall remain with the governing body of the cooperating cities and counties.
(c) Each participating city or county may continue to have its own planning commission or board but may, under the joint agreement and in the interest of economy and efficiency and in the interest of uniform standards and procedures, request the metropolitan or regional planning commission to assume duties and functions of local planning agencies, in whole or in part.