In fixing the just, reasonable, and compensatory rates, joint rates, tolls, classifications, charges, or rentals to be observed and charged for service by any public utility, the public utilities commission shall, in action upon an application filed pursuant to section 4909.18 of the Revised Code, require a public utility to file a report showing the proportionate amounts of the valuation of the property of the utility, as determined under section 4909.05 of the Revised Code, and the proportionate amounts of the revenues and expenses of the utility that are proposed to be considered as attributable to the service area involved in the application.

“Valuation,” as used in this section, may include, with respect to a natural gas, water-works, or sewage disposal system company, projected valuation as of the date certain, if applicable because of a future date certain under section 4909.15 of the Revised Code.