The State Department of Revenue shall charge Covington County for collecting the special county taxes levied such amount or percentage of total collections as may be agreed upon by the Commissioner of Revenue and the county governing body, but such charge shall not in any event exceed three percent of the total amount of special county taxes collected hereunder within the county. Such charge for collecting the special taxes for the county may be deducted each month from the special sales and special use taxes collected before certifying the amount of the proceeds thereof due Covington County for that month. The Commissioner of Revenue shall pay into the State Treasury all county taxes collected under this subpart, as such taxes are received by the Department of Revenue; and on or before the first day of each successive month (commencing with the month following the month in which the department makes the first collections hereunder), the commissioner shall certify to the Comptroller the amount of taxes collected under this subpart and paid by him or her into the State Treasury for the benefit of Covington County during the month immediately preceding the making of such certificate. Provided, however, that before certifying the amount of the taxes paid into the State Treasury for the benefit of the county during each month, the commissioner may deduct from the taxes collected in the month the charges due the department for the collection of the taxes for the county. It shall be the duty of the Comptroller to issue his or her warrant each month payable to the custodian of the public funds of Covington County in an amount equal to the amount so certified by the Commissioner of Revenue as having been collected for the use of the county. The custodian of public funds for Covington County shall maintain separate records of such special account.