1. (a) For each rate year in an electricity supplier's multi-year rate plan, the commission shall determine a customer affordability performance metric for that electricity supplier by calculating the difference between:

   1. (1) the average annual percentage change (rounded to nearest one-tenth percent (0.1%)) in the electricity supplier's average monthly residential bill over the course of the most recently concluded five (5) calendar years (normalized for weather if not otherwise normalized for weather through a rate adjustment mechanism described in section 1(b)(3) of this chapter); minus

   2. (2) the average annual percentage change (rounded to nearest one-tenth percent (0.1%)) in seasonally adjusted electricity prices for the United States as measured by the Consumer Price Index, as published by the United States Bureau of Labor Statistics, over the course of the most recently concluded five (5) calendar years;

      as reported in the most recent customer affordability performance report submitted to the commission by the electricity supplier under section 18 of this chapter. The difference calculated under this subsection is the electricity supplier's customer affordability performance metric for the rate year.

2. (b) If the electricity supplier's customer affordability performance metric under subsection (a) is a positive number that exceeds two (2) percentage points, the commission shall adjust the electricity supplier's authorized return for the rate year downward by not more than one (1) basis point.
3. (c) If the electricity supplier's customer affordability performance metric under subsection (a) is a negative number that when multiplied by negative one (-1) exceeds two (2) percentage points, the commission shall adjust the electricity supplier's authorized return for the rate year upward by not more than one (1) basis point.

As added by P.L.36-2026, SEC.10.