Ind. Code § 8-1-31-14
An adjustment amount proposed under section 8 of this chapter may be calculated based on a reasonable estimate of meter size in the period in which the charge will be in effect. At the end of each twelve (12) month recovery period following the date on which the commission initially approves an adjustment amount for an eligible utility following the eligible utility's most recent general rate case, and using procedures approved by the commission, the eligible utility shall reconcile the difference between adjustment revenues and infrastructure improvement costs during the recovery period and recover or refund the difference, as appropriate, through additional adjustments. In the case of an eligible utility that is a municipally owned utility or a not-for-profit utility, the adjustment amount shall be reset to zero (0) after all previously approved infrastructure improvement costs have been collected, with the exception of any amount necessary to reconcile the difference between adjustment revenues and infrastructure improvement costs.
IC 8-1-31-14