In a proceeding involving a proposed rate change, the gas utility has the burden of proving that:

1. (1) the rate change is just and reasonable, if the utility proposes the change; or
2. (2) an existing rate is just and reasonable, if the proposal is to reduce the rate.

Acts 1997, 75th Leg., ch. 166, Sec. 1, eff. Sept. 1, 1997.