@ TOM, your not confusing the unwrap of a stereo recording into a surround recording? thats the cheap cheating way of doing it. Nick really did go and get the multitracks and do it properly with panning so that the rear channels had some good use.
Not at all, Mark. I've just tried to point out that he first did the stereo mixes from the multitracks, then, from the same mixing session, he just spread the panorama settings to surround while keeping everything else unchanged.
It's practically impossible to create a new stereo mix that's so close to the original stereo mix when you start with surround and then just make a downmix. This has to do with the different perceptions. With five equal channels, individual instruments are less "in each other's way" - a problem that requires a lot of attention in stereo mixing and which can be rather neglected when mixing in surround.