Legislative members of the Commission shall receive such compensation as provided in § 30-19.12 and shall be reimbursed for all reasonable and necessary expenses incurred in the performance of their duties as provided in §§ 2.2-2813 and 2.2-2825. Unless otherwise approved in writing by the chairman of the Commission and the executive director of the Commission, nonlegislative citizen members shall only be reimbursed for travel originating and ending within the Commonwealth for the purpose of attending meetings. However, all such compensation and expenses shall be paid from existing appropriations to the Commission or, if unfunded, shall be approved by the Joint Rules Committee.