(1) The presiding officer, where practicable, must encourage all parties to agree on the identity and number of witnesses who are to give expert testimony by:

(a) Selecting one or more to speak for all parties; or

(b) Limiting the number for each party.

(2) If the parties cannot agree, the presiding officer must require them to submit written statements to all parties with the names, addresses, and qualifications of their respective expert witnesses on a date determined by the presiding officer sufficiently in advance of the hearing to allow the other parties to investigate the witness' qualifications.

(3) The presiding officer must require parties to submit the underlying data for statements and exhibits they provide sufficiently in advance of the hearing to allow the other parties to cross examine the expert witness(es) at the hearing. However, the presiding officer must restrict to a minimum placing the data in the record.

(4) No former employees of our agency may appear, except with the director's or director's designee's permission, as expert witnesses on behalf of other parties in a proceeding involving a matter that was under consideration by the agency when the former employee was employed by the commission.