(1) Briefs. Briefs on exceptions may be filed by any party within 20 days after the proposed order is filed. 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 commissioner.

(2) Contents. Briefs on exceptions and replies 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. Parties are cautioned that vague assertions as to what the record shows or doesn't show, without citation to the precise portion of the record, may be accorded little attention.

(3) Copies. An original and six copies of each brief on exceptions and reply shall be filed with the commission, and be accompanied by a certificate of service showing proof of service of copies of same on each attorney or party or parties.