The terms and conditions under which a public utility offers its services and facilities to the public shall be governed strictly by the provisions of its currently effective tariffs. A legally filed and effective tariff rate, charge, toll, rental, rule, regulation, or condition of service may not be changed except in the manner provided in this chapter. If more than one tariff rate or charge can reasonably be applied for billing purposes the one most advantageous to the customer shall be used.
Alaska Legal Code