18 C.F.R. § 385.705 – Additional powers of presiding officer with respect to briefs (Rule 705).

(a) Limitations on briefs. A presiding officer, with due regard to the nature of the proceeding, may limit the length of any brief to be filed under Rule 706.
(b) Additional briefs and other filings. If appropriate, the presiding officer may permit or require briefs or other filings in addition to those provided for in Rule 706.