The board shall meet at least six days a year but shall not meet more than 36 days in one year. All meetings shall be open to the public except that the board may hold restricted attendance sessions to prepare, give, and grade examinations and to deliberate in connection with the decision in a contested case. The division director shall be secretary of the board and, in addition to his duties as prescribed by Code Section 43-1-3, shall perform such other administrative duties as may be prescribed by the board. All legal process and all documents required by law to be served upon or filed with the board shall be served upon or filed with the division director at his office in Atlanta. All official records of the board, or affidavits by the division director as to the content of such records, shall be prima-facie evidence of all matters required to be kept therein.