No, I don't think your full of horsehock. You make perfect sense. After Great Gig in the Sky (or Any Colour You Like, I always get them mixed up), it pauses for the first time in the album. After delving into the Floyd experience there, it needs something to bring you back into the real world for a while. To do this, they need some sort of a 'rockin' tune to 'wake you up' from your sleep, so to speak. Afterwards you return to the Floyd world with Us and Them, one of my favorite tracks on Dark Side of the Moon. As Not Now John said before, it keeps building up until the climax and the end. You've then just finished the trip known as the Dark Side of the Moon.