Each participating municipality or instrumentality that employs an employee who is an elected trustee shall make available to the elected trustee at least 20 days of paid leave of absence per year for the purpose of attending meetings of the Board of Trustees, committee meetings of the Board of Trustees, and seminars regarding issues for which the Board of Trustees is responsible. The Fund may reimburse affected participating municipalities and instrumentalities for the actual cost of hiring a substitute employee during such leaves of absence.