I suspect part of this "mess" is because in the early days of BIAB when it ran on an Atari ST, to speed up entry, the shift key was optional. Shift-3 gave a '#' symbol, so BIAB let you use 3 (without the shift) to get the same character.

Something seems to have changed for 2016 that has broken this "strange" mapping of keys. I guess they didn't have enough odd keyboards to test it all on.

Regards