Here's my theory
It's getting near to closing out the track list and 2 songs are battling for a spot on the album.....APOM and SW. Michael doesn't care which one makes it because he wrote both so MJ and Q get help from Frank to pick a song. They pick APOM and with that, they head back to the studio to mix, master and add final touches. We've heard APOM 1985 mix and we can hear the difference with Quincy on board
If there is a Quincy mix of SW, how come it wasn't included on Bad SE 2001? We get Quincy talking briefly about the song only for them to play Michaels version? Why not include the one that almost made the album?