(1) Upon completion of the conversion contemplated by this part, the public utility shall present the governing body with its verified bill for conversion costs as computed pursuant to 69-4-314, but based upon the actual cost of constructing the underground facility rather than the estimated cost of the facility. In the event the conversion costs are less than the estimated conversion costs, each assessed owner within the improvement district shall receive the benefit, prorated in such form and at such time or times as the governing body may determine. The bill of the public utility shall be paid within 30 days by the governing body from the improvement district funds or such other source as is properly designated by the governing body.
(2) In determining the actual cost of constructing the underground facility, the public utility shall use its standard accounting procedures, such as the uniform system of accounts as defined by the federal communications commission, federal power commission, or Montana public service commission and as is in use at the time of the conversion by the public utility involved.