The Commission approved and adopted on May 29, 1945, the following conclusions as to its powers of suspension of rate schedules under section 205 of the act:
(a) The Commission cannot suspend a rate schedule after its effective date.
(b) The Commission can suspend any new schedule making any change in an existing filed rate schedule, including any rate, charge, classification, or service, or in any rule, regulation, or contract relating thereto, contained in the filed schedule.
(c) Included in such changes which may be suspended are:
(3) Discriminatory changes.
(4) Cancellation or notice of termination.
(5) Changes in classification, service, rule, regulation or contract.
(d) Immaterial, unimportant or routine changes will not be suspended.
(e) During suspension, the prior existing rate schedule continues in effect and should not be changed during suspension.
(f) Changes under escalator clauses may be suspended as changes in existing filed schedules.
(g) Suspension of a rate schedule, within the ambit of the Commission's statutory authority is a matter within the discretion of the Commission.