69-12-501. Rate schedules to be maintained. (1) A Class A motor carrier issued a certificate shall maintain on file with the commission, if applicable, a full and complete schedule of its rates, fares, charges, classifications, and rules of service and any and all tariff provisions relating to rates, fares, charges, classifications, or rules. A schedule on file and approved on March 7, 1961, remains in full force and effect until changed or modified by the commission or by the carrier with the approval of the commission.
(2) A change, modification, alteration, increase, or decrease in any rate, fare, charge, classification, or rule of service may not be made by a motor carrier without first obtaining the approval of the commission. The commission shall prescribe rules providing for the form and style of all schedules and tariffs and for the procedures to be followed in filing or publishing any changes or modifications of schedules and tariffs.