At any time, the Commission may investigate and determine the fair value of the property of a public service company used and useful in providing service to the public. The valuation: is not final until the Commission: serves on the public service company a copy of the order setting the proposed valuation and the method used to set the valuation; and allows a reasonable time in which to file a protest; and is final if a protest is not filed within the time specified in the order. If a timely protest is filed, the Commission shall enter a final valuation by order after hearing. All final valuations are prima facie evidence of value in proceedings under this division.