(1) If, after the investigation and hearing thereon, the Arkansas Department of Transportation finds the new rate to be unjust, unreasonable, discriminatory, or otherwise in violation of the law or rules of the department, it shall determine and fix the just and reasonable rate to be charged or applied by the utility for the service in question, from and after the time the new rate took effect.
(2) Until rate schedules in compliance with the department’s order can be filed and approved, any rate increase allowed in the department's order shall be apportioned among all classes of customers and shall become effective on all bills rendered thereafter through a temporary surcharge or other equitable means, as shall be prescribed in the order.