Third question is about something that confuses me, and I can't find examples right now. But there are quite a few songs, where ending is incoherent with the whole song. What's that about? I red that back in the days before LPs, when you could only get 3-4 minutes on one side or record, bands tied to sneak in demos, by patching some new material to existing song. The length of pop music single did not increase much since then. Could it be that early technological issues left mark on arrangement tradition. Or is there something else? This does not happen in other genres though. Nowadays bands need filler material for CDs. The only example I found right now is from Alex Wilson version of "Englishman in New York". Last minute is different groove than first 3:30. Still the same melody.