Oral argument

(a) If the parties have agreed, or the prehearing order has established, that an administrative hearing will be decided on a written motion or on the written record and briefs, the administrative law judge will hear oral argument upon a written request of a party that is filed within three days after service of the last brief allowed to be filed or as provided in a prehearing order. (b) Oral argument on a motion that is not covered in (a) of this section is at the discretion of the administrative law judge.