The officer presiding at a hearing shall have all the powers necessary or appropriate to conduct a fair and full hearing, including the powers:

(a) To regulate the course of the proceedings;

(b) To dispose of procedural requests, objections, and comparable matters;

(c) To confine the presentations to the issues specified in the notice of hearing, or, where no issues are specified, to matters pertinent to the proposed rule;

(d) To regulate the conduct of those present at the hearing by appropriate means;

(e) In his discretion, to permit cross- examination of any witness;

(f) To take official notice of material facts not appearing in the evidence in the record, so long as parties are entitled, on timely request, to an opportunity to show the contrary; and

(g) In his discretion, to keep the record open for a reasonable, stated time to receive written recommendations, and supporting reasons, and additional data, views, and arguments from any person who has participated in the oral proceeding.