(1) Briefs on exceptions may be filed by any party within 20 days after the proposed order is filed. Response briefs opposing exceptions may be filed within ten days thereafter. Enlargement of time may be granted for good cause shown with leave of a presiding officer or hearing examiner.
(2) Briefs on exceptions and response briefs must specifically set forth the precise portions of the proposed decision to which the exception is taken, the reason for the exception, authorities on which the party relies, and specific citations to the transcript, if prepared.
(3) An original of each brief on exceptions and response briefs shall be filed with the commission, and be accompanied by a certificate of service showing proof of service on each party's representative.