Drill Ship Seatime Question

Do the new Foreign Flag Ultra deep Drill ships count for USCG unlimited sea time for licensed officers or do they carry MODU restriction? I understant that it is possible to get unlim time for 3rd-2nd Mate, but can only get 180 days on a drill ship for unlim Master or CE and need to get the rest on a conventional ship. Is that correct or are people getting unlim time all the way up on these? Is that right?