Section 757.310 - Prohibition related to charges for service(1) A public utility may not charge a customer a rate or an amount for a service that is different from the rate or amount prescribed in the schedules or tariffs for the public utility.(2) A public utility may not charge a customer a rate or an amount for a service that is different from the rate or amount the public utility charges any other customer for a like and contemporaneous service under substantially similar circumstances.(3) A difference in rates or amounts charged does not constitute a violation of subsection (2) of this section if the difference is based on: (a) Service classification under ORS 757.230;(b) Contracts for services under ORS 757.516; or(c) An optional schedule or tariff for the provision of energy service that takes into account a customer's past energy usage and provides price incentives designed to encourage changes in the customer's energy usage that correspond to changes in the cost of providing energy. Amended by 1971 c.655 §78; 1987 c.900 §2; 1993 c.485 §3; 2005 c. 594, § 1