In addition to any other compensation to which a member of a county governing authority is entitled under general or local law, any such official who has been awarded a certificate from the University of Georgia, evidencing his or her successful completion of the voluntary course of training administered by the Carl Vinson Institute of Government resulting in designation as a certified county commissioner shall be entitled to a compensation supplement of $100.00 per month. With regard to members of the governing authority of a consolidated government, designation either as a certified county commissioner or a certified municipal official by the Carl Vinson Institute of Government shall be acceptable.