....and I had an idea; What if I switched the Sky Sanctuary music with Sanctuary Falls from ASRT? So I turned the in game music off, plugged the USB with the Sactuary Falls MP3 file into my Xbox, started Sky Sanctuary Act 2, and started the music.
WOW. These two were meant to go together! Even though the tempo on Sanctuary falls is slower, it still fits perfectley! Back in Time also seemed to work brilliantly with the stage!
I also tried Seaside Hill with Ocean View's music, and same result.