I'm still fretting a bit about the descent thing . . . I'm sure my thoughts are greatly shaped by the conditions in which I dive. In Puget Sound, particularly in the summertime, it can be true that the viz in the top 20 feet or so is measured in inches to one or two feet. If you don't stay right together, you will lose your buddy/ies and have to come back up and start over. A star descent (if water is still) or a shoulder-to-shoulder descent (if going into current) is really the only way to keep the team. And if you have agreed to do bubble checks at 20 feet, you have to be able to arrest your descent there briefly.
I also found that, in the South Florida currents, it was pretty important to stay very close together while dropping, because otherwise the water was going to sweep us apart, and I am not strong enough to fight it very effectively.
Unlike in class, no one I know dives shoulder-to-shoulder in perfect position all the time. It's too restrictive, and unnecessary in anything but the most unfriendly conditions (and I don't stay down in those conditions very long!). But for descent and ascent, I completely subscribe to the Fundies idea of a tight team. I hate messes.