(1) Whenever a state agency as defined in RCW 34.12.020(4) conducts a hearing which is not presided over by officials of the agency who are to render the final decision, the agency shall use one of the following methods for requesting assignment of an administrative law judge:

(a) Not less than twenty days prior to the date of the hearing, notify the chief administrative law judge or his or her designee of the date, time, and place of the hearing and request assignment of an administrative law judge to preside over the hearing, or

(b) File with the office of administrative hearings a copy of the hearing file, which filing shall be deemed to be a request for assignment of an administrative law judge to issue the notice of hearing and preside over the hearing, or

(c) Schedule its hearings to be held at times and places reserved and provided to the agency for that purpose by the office of administrative hearings.

(2) Motions of prejudice with supporting affidavits under RCW 34.12.050 must be filed at least three days prior to the hearing or to any earlier stage of the adjudicative proceeding at which the administrative law judge may be required to issue a discretionary ruling. If the notice of hearing does not state the name of the presiding administrative law judge, the chief administrative law judge or his or her designee shall make such assignment at least five days prior to the hearing and shall disclose the assignment to any party or representative making inquiry. Subsequent motions of prejudice filed by the same party in the same proceeding shall be ruled upon by the chief administrative law judge or his or her designee.