Wis. Admin. Code LIRC § 1.11
Either party may request the commission to establish a briefing schedule. Requests to file briefs may be made in the petition for review, in an answer, or in writing after the petition and answer. The commission may deny a request to file a brief which is not made in a petition or answer if the commission has already reviewed the case but not yet issued its decision at the time the request is made. Each party may file with the commission briefs or memoranda within the time limits of the briefing schedule established by the commission. Requests for extensions of time for filing briefs shall be made in writing. Extensions may be approved in writing upon good cause shown. A party filing a brief or memorandum with the commission shall furnish a copy to the opposing party.
Wis. Admin. Code Labor and Industry Review Commission § LIRC 1.11