For MIDI styles, there are settings as to how "jazzy" the arrangement should be. You can specify whether to jazz-up or jazz-down the chords. I suspect that's where some of the "off" notes come from. That being said, for standard MIDI tracks (not SuperMIDI), the arrangement you get is based on rhythmic phrase that have been normalized to a C7 chord. The other chord extensions are based on the basic C7 chord. The engine then picks on of the available rhythmic phrases based on its weighting, or in some cases whether it is flagged as a special case (every fourth bar, a jump to a fifth, whatever), is transposed accordingly with the additional notes added to complete the chord, and that's what you get. Yes, sometimes you get some bad notes, but again, the engine picks them based on how "jazzy" your setting is.

For RealTracks-based styles, you can set the song use simpler arrangements and now natural arrangements.

All these things go into determining what gets played, and sometimes it gets it right and other times it gets it wrong. But hey, so does a live band, too. Just regenerate until it's too your liking, then lock it down if it is of great concern.

I'm sure there's a lot more that goes on behind the scenes, but that's my rudimentary understanding. The best person to answer about MIDI styles, however, is probably Bob "Notes" Norton, since he has created so many of his own styles for sale that he is intimately knowledgeable about the output produced by BIAB (whether by any inside knowledge or observational intuition).

John

Laptop-HP Omen I7 Win11Pro 32GB 2x2TB, 1x4TB SSD
Desktop-ASUS-I7 Win10Pro 32GB 2x1.5TB, 2x2TB, 1x4TB SATA

BB2025/UMC404HD/Casios/Cakewalk/Reaper/Studio One/MixBus/Notion/Finale/Dorico/Noteworthy/NI/Halion/IK

http://www.sus4chord.com