Ind. Code § 8-1-31.6-14

Sec. 14. An adjustment amount proposed under section 10 of this chapter may be calculated based on a reasonable estimate of equivalent meters in the period in which the charge will be in effect. At the end of each twelve (12) month period following the date on which the commission initially approves an adjustment amount for a municipally owned utility following the utility's most recent general rate case, the municipally owned utility, using procedures approved by the commission, shall reconcile the difference between revenues under the adjustment rider and customer lead service line improvement costs during that period and recover or refund the difference, as appropriate, through additional adjustments to the adjustment rider.