(a) Prepared written direct and rebuttal testimony. Unless the presiding officer orders such testimony to be presented orally, direct and rebuttal testimony of a witness in a hearing must be prepared and submitted in written form, as required by Rule 507. Any witness submitting written testimony must be available for cross-examination, as provided in this subpart.

(b) Oral testimony during hearing. Oral examination of a witness in a hearing must be conducted under oath and in the presence of the presiding officer, with opportunity for all participants to question the witness to the extent consistent with Rules 504(b)(17), 505, and 509(a).