Yes, we are close. I think perhaps you meant to write 'accept' instead of 'except', and I would agree.

In other words, the sus2 does not contain the 3rd of the chord. The add2 and add9 do.

Add2 and add9 are not the same; the difference is the register of the note that is the second or the ninth relative to the root. It is the same pitch but in a different register (octave).

However, yes, as I showed, BIAB treats all three as the same. That doesn't mean you will get the right chord or the wrong chord in any given instance. BIAB plays chord voicings somewhat at random, limited by what the RealTracks artist recorded. In the case of MIDI, except for voicing, then the chord should be correct but, as noted in this case, BIAB does not distinguish between the three chord types.

So, since this is the Wishlist, I think what you may be requesting is that BIAB not treat all three of these chord types the same. For that, +1. I've written about this for decades. I think that the MIDI could be fixed in programming. But to support the differences in RealTracks, it would probably involve a serious change to the indexing of the performances already recorded.

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