Are you sure Matt? I really thought that BIAB used some sort of replacement when the chord is not present in the Real Track recordings. It happens for sure for usertracks, so I thought the same would be true for midi tracks and realtracks. I could be wrong of course.
Anyway, my question still applies for usertracks, as it is clear that BIAB seem to try to playback a "similar" chord when the typed chord is not found in the UT recordings. It would be nice to know what the rules are.