The Montgomery Commission and an employee organization certified as the exclusive representative of a bargaining unit shall execute a collective bargaining agreement incorporating all matters of agreement on wages, hours, and other terms and conditions of employment. If a collective bargaining agreement provides for a grievance procedure, that grievance procedure shall be the only procedure for employees in the bargaining unit. The collective bargaining agreement may include an agency shop or other union security provision. The collective bargaining agreement supersedes any conflicting regulation or administrative policy of the Montgomery Commission. A collective bargaining agreement takes effect on the approval of the Montgomery Commission and the membership of the employee organization representing the bargaining unit. A single year or multiple–year collective bargaining agreement shall expire at the close of the appropriate fiscal year. If a provision in a collective bargaining agreement is ruled invalid or is not funded adequately, the rest of the agreement remains in effect unless reopened under § 16–313(b) of this subtitle.