Limiting number of witnesses. The Board may limit appropriately the num

ber of witnesses who may be heard upon any issue, to eliminate unduly repetitious or cumulative evidence without prejudice to the substantive rights of any party. 9 Revised October 2023 3.27. Additional evidence. At the hearing, the Board may, if deemed advisable, and subject to the appropriate order to protect the substantive rights of any party, author- ize any participant to file specific documentary evidence as a part of the record within a fixed time, expiring not less than ten (10) days before the date fixed for filing and serving briefs.