(1) As to rates or services, no public utility shall make or grant any unreasonable preference or advantage to any corporation or person or subject any corporation or person to any unreasonable prejudice or disadvantage.
(2) No public utility shall establish or maintain any unreasonable difference as to rates or services, either as between localities or as between classes of service.
(3) The commission, in the exercise of its jurisdiction granted by this act, may fix uniform rates applicable throughout the territory served by any public utility whenever in its judgment public interest requires such uniform rates.
(4) The commission may determine any question or fact arising under this section.