(2) Every public utility shall file with and as part of every such schedule all rules and regulations that in any manner affect the rates charged or to be charged for any service. Every public utility shall also file with the commission copies of interstate rate schedules and rules and regulations issued by it or to which it is a party.
(3) Where a schedule of joint rates or charges is or may be in force between two or more public utilities, such schedules shall in like manner be printed and filed with the commission. [Amended by 1971 c.655 §70]