Go to the 30 minute mark of this video Stuart and you will see a demo that hits on everything you are describing and yes, ideally, the purpose of this skill is to position yourself in such a way that you can deal with an entanglement or your cam band. I will say this though: The instructor in this demo is wearing a very thin wetsuit and has a weight belt on, which makes executing this skill while neutrally buoyant and in horizontal or vertical trim a whole lot easier than doing it this same way in a 7mm wetsuit or drysuit and fully integrated weights. It is very easy to start floating up and away from your rig if you have the rig too far away from you and are not using it and its weight to keep you together and neutral or together and negative.
Thanks! The buoyancy control there was not perfect. Nevertheless, that video was overall the best R&R demo of any of the videos I watched. I really don't think I could do it that well. At least, not without practicing it some first. I could do it - but I suspect it would be far from "demo quality". For my DM training, when I did my demo of the U/W R&R, I did it like I had seen the OW instructors I was working with do it - on my knees. I felt like I was choking down some pride to do it that way. But, I feel like part of DM training is showing that I am a team player and have no problem following the leader (assuming it's not a safety issue, of course). Just because I think there's a better way doesn't mean I'm going to go against what the instructor is teaching when I am being their DM.
Anyway, it was definitely cool to see someone do it in proper trim and really take their rig off and put it back on.