The Gas Charge(s) shall represent the utility's estimate of recoverable gas costs (as prescribed in Section 525.40) to be incurred during the base period, with an adjustment to such costs through use of Adjustment Factors (as prescribed in Sections 525.50, 525.60 and 525.70) . Any Gas Charge(s) established to recover commodity gas costs (separately or in conjunction with non-commodity gas costs) shall use an estimate of the recoverable costs to be incurred during the effective month. Any Gas Charge(s) established to recover only non-commodity gas costs shall use an estimate of the recoverable costs to be incurred during the remaining months of the reconciliation year.
Ill. Admin. Code tit. 83, § 525.30