I'm not sure how much stock I would put in what is said on DL website actually reflecting reality. Companion on same reservation definitely clears at same time and priority as the Medallion. My impression is that companions on separate reservations clear independently and not necessarily at same priority. Perhaps someone with more experience with companions on separate reservations can comment. Also, it seems both companion and Medallion must be on "paid" reservations to link separate reservations for upgrades (and system will not allow mixing award and revenue fares with companion upgrades on separate reservations). There used to be some language to this effect, but it doesn't seem to be there any more.