(a) All motions and requests prior to the hearing shall be submitted in writing to the hearing officer or, where no hearing officer has been designated, to the commission. Copies of motion papers shall be served upon all parties. Motions made during the course of a hearing may be stated orally and shall be made a part of the record.

(b) The hearing officer shall rule upon all motions and requests prior to the submission of his report to the commission. The commission shall rule upon all motions and requests submitted prior to designation of a hearing officer or after receipt of the hearing officer's report.