The chairman and members of the commission shall receive per diem in the amount set forth in Section 25-3-69 for each and every day actually and necessarily spent in attending the meetings of the commission, and shall be reimbursed for their reasonable subsistence and traveling expenses necessarily incurred in the performance of their duties in accordance with Section 25-3-41. The chairman shall require itemized statements of all such reimbursable expenses and shall audit or cause to be audited such statements before approving the same for payment.