(a) Reject a PAR which is timely filed if it is insufficient or defective, but may provide a specified period of time within which to perfect the PAR.

(b) Make such investigation of the facts, hold such conferences, and require the filing of such reports, evidence, affidavits, or other material relevant to the proceeding as he may deem necessary or appropriate.

(c) Forward to, or make available for inspection by either party, any relevant evidence, and afford an opportunity to file rebuttal thereto.

(d) For good cause shown, accept for filing any papers, other than a PAR, even though not filed within the time required by this Part.

(e) Require any person to appear or produce documents, or both, pursuant to a subpoena issued by the commissioner.

(f) Grant or order a hearing.