I think you defined the problem, Matt. I don't think you can do repeats or 2nd endings in the Mac version, which seems really strange. I was assuming that you could because on the BIAB website, under "Band-in-a-Box Macintosh" -> PG Music Video Tutorials Band-in-a-Box for Macintosh, there is a video in the Intermediate section entitled "BIAB: Repeats & Fake Sheet Mode", but it apparently doesn't apply to the Mac version even though it's in the Mac section, which is very misleading and somewhat annoying, considering how much time I've spent trying to figure this out. I looked at my old 2012 Mac version, and it doesn't have any of these commands either.
Thanks.
WBD