The 911 Board shall reimburse the Department of Examiners of Public Accounts to the extent of any unused funds retained for administrative expenses under this section or Section 11-98-5.2(b) for the amount of actual costs incurred in carrying out the requirements placed upon the Department of Examiners of Public Accounts by this chapter, as evidenced by invoice presented to the board. By January 1, 2013, the Department of Examiners of Public Accounts shall provide the 911 Board with a projection of its annual costs in meeting the requirements of this chapter, which shall be treated and retained by the 911 Board as an administrative fee in addition to the administrative allowance specified in Section 11-98-5.2(b). The invoiced amount shall be due and payable within 30 days of presentment.