The remainder so determined, herein called the total assessment, shall be allocated to, and paid by, such public utilities in the manner prescribed. If the General Assembly fails to approve the commission's budget for the purposes of this part, by March 30, the commission shall assess public utilities on the basis of the last approved operating budget. At such time as the General Assembly approves the proposed budget the commission shall have the authority to make an adjustment in the assessments to reflect the approved budget. If, subsequent to the approval of the budget, the commission determines that a supplemental budget may be needed, the commission shall submit its request for that supplemental budget simultaneously to the Governor and the chairmen of the House and Senate Appropriations Committees.
66 Pa.C.S. § 510