Respondents bring forth a number of assignments of error and challenge the sufficiency of the evidence to fulfill any one of the three statutory requirements set forth in G.S. 62436(c). The statute provides that the Commission may require supplier refunds to be passed through to gas customers where three prerequisites are met. These are: (1) that the refund be prac*450ticable, (2) that the charges have been included in rates paid by the customers, and (3) that the company has had a reasonable rate of return exclusive of the refund. If all of these requirements are met, the company may be ordered “to distribute said refund among said customers in proportion to their payment of the charges refunded.” G.S. 62436(c).
It is argued by respondents that the statutory language clearly requires that it must be practicable to make the refunds to the customers who paid the charges, and that the Commission’s award to current customers of the gas companies was error.
The Public Staff defends the Commission’s award as being consistent with the Commission’s established policy. While we might be persuaded by prior policy if the statute were found to be ambiguous, such policy is impliedly overruled to the extent that it is inconsistent with the clear wording of a subsequent statute. Here, the wording of the statute clearly requires that refunds be made to the customers who paid the charges, and that these refunds be contingent upon practicability.
Determination of the identity of those customers to whom refunds might be due here, and of the relative proportion of their interests, in our view, would be impracticable since the charges in question relate to periods ranging from ten- twenty-three years prior to the supplier refunds. Therefore, one of the statutory prerequisites is unfulfilled, no refund is called for, and the Commission’s contrary conclusion was erroneous.
We find it unnecessary to discuss the remaining assignments of error since our holding on the first argument requires that the judgment of the Commission be reversed.
Reversed.
Judges Clark and Whichard concur.