The findings of the commission, as made and filed, when properly certified by the commission, shall be admissible as evidence in any proceeding or hearing before the commission or any court in which the commission, the state, or any officer, department, or institution thereof, or any county, city, municipality, or other body politic and the public utility affected thereby, may be interested, whether arising under the provisions of this chapter or otherwise. Such findings, when so introduced, shall be conclusive evidence of the facts therein stated as of the date therein stated under conditions then existing and such facts can be controverted only by showing a subsequent change in conditions bearing upon the facts therein determined.