(a) The commission, or a committee thereof, may require by order instituting hearings, prehearing conference order, or other proper notice that evidence on specified issues of fact or matters of technical expertise be presented as sworn testimony. Such requirements shall not preclude unsworn oral or written comments from being offered in the proceeding.

(b) The presiding member may require that prepared written testimony or other evidence be submitted in advance of any hearing, for the purpose of facilitating the orderly consideration of issues at the hearing.