Thanks so much! It looks like BIAB defaults to 24 bit, found how to set that to 16 and it seems to be working now, thanks again!
The BIAB support was friendly and helpful but they said there was no way to specify the format, but after digging a bit I found that there are 2 ways to create a .WAV file; one is "File-Save Special-Choose WAV" (with this there is no way to change from 24 to 16 bit, but under the Audio menu there is an "Export Song As Audio File" where you can).