(1) The salaries and expenses of the Arkansas Public Service Commission shall be paid monthly upon certificate and vouchers, as required by law.
(2) If it becomes necessary to pay for transportation, costs, or other expenses of a similar nature during any current month, the payments may be drawn in advance upon certificate of the commissioners. However, the payments are to be embraced thereafter in the monthly statement to be made as required by law, showing the expenses to have been paid.