(a) General rule.--The expenses of the Pennsylvania Public Utility Commission in administering this subchapter shall be assessed by the commission against the affected retail electric suppliers on the following basis:

(1) Expenses which relate to the preparation or review of maps to establish the certified territory of a single retail electric supplier in any county or other area where there is no other retail electric supplier shall be assessed solely to such single retail electric supplier.

(2) Expenses which relate to the preparation or review of maps to establish the certified territories of two or more retail electric suppliers in any county or other area where there are two or more retail electric suppliers shall be assessed in equal shares among such retail electric suppliers.

(3) Expenses which relate to the consideration and disposition of alleged errors pursuant to section 7354(e) (relating to examination and correction of maps) and the consideration and disposition of proposed adjustments pursuant to section 7354(f) (relating to adjustment of certified territories) shall be assessed in equal shares among the retail electric suppliers affected thereby.

(4) Expenses which relate to the enforcement by the commission of compliance with this subchapter shall be assessed in equal shares against the retail electric supplier or suppliers to which an order of enforcement is directed. If the enforcement proceedings were initiated by a retail electric supplier or suppliers and if no order of enforcement is issued by the commission, the expenses shall be assessed in equal shares against the retail electric supplier or suppliers initiating the proceedings.

(5) Any other expenses of the commission shall be assessed by the commission in equal shares among the retail electric suppliers that are subject to this subchapter.

(b) Estimated expenses.--The commission may, if it deems such action appropriate, assess expenses on the basis of estimates made by it with appropriate adjustment or credit after final determination of the expenses.