(1) No auto transportation company will charge, demand, collect, or receive a greater, lesser, or different compensation for transportation of persons, than the rates that are contained in that company's effective tariff filed with the commission. Further, no auto transportation may extend to any person any privilege that is not uniformly extended to all persons under the same circumstances.

(2) An auto transportation company wishing to provide service at free or reduced rates must first publish those free or reduced rates in its filed tariff in accordance with RCW 81.28.080.

(3) If an auto transportation company chooses to provide service at free or reduced rates, the company must publish in its tariff:

(a) A detailed description of the customer class and criteria to qualify;

(b) The service provided;

(c) The expiration date, if any; and

(d) The applicable rate(s), amount of reduction (such as, twenty percent), or if free, "$0.00" or "no charge."

(4) The auto transportation company must record the number of passengers transported under each free or reduced rate published in its tariff in accordance with RCW 81.28.080.