(1) If the commission intends to intervene in a proceeding, the commission must file a notice of intervention in accordance with form 5.
(2) Not later than 3 days before the date fixed for the hearing at which the commission intends to appear in the proceeding, the commission must serve a copy of the notice, and any affidavit on which it intends to rely, on the plaintiff and on any other party to the proceeding.