There is an interesting(?) new feature introduced in Band-in-a-Box 2017 called "Natural Arrangements Option
In the New Features Guide
for Version 2017 it says this:
"If you give a pro musician a complicated chord progression with fancy extensions like C7b9b13 or Gm11, the musician may reinterpret these rather than playing them exactly as written. This can achieve a much better sounding arrangement because the musician has freedom to choose from similar chord extensions. Now you can get Band-in-a-Box to do the same thing. You can set this on a global basis (all songs, all tracks), song basis (current song, all tracks), or individual tracks (current song, specific track(s))."
I would ask the pro musicians on this forum if the first sentence opening statement is true? When you are improvising, do you reinterpret the chords? It would seem to me that you would need a very good rhythm section to pick up on any chords you change. Or perhaps you would ask them to play simple chords without the complicated chord extensions?
I think I did read once that Stan Getz often did change not only the structure of chords, but the chord progression as well. I have also seen scored band arrangements where the chords for the improvised section are somewhat simplified to the ones used in the arrangement. These two facts would seem to indicate it is sometimes the case that simplified chords are used in improvisations.
On the other hand, I have not seen this simplification suggested in any of the many tutor books I have on jazz improvisation. Most of them go to extreme lengths to explain what special scales you should use for complex chords.
I am not a pro but I have been improvising jazz all my adult life and I have never tried to mess with the chords in any way when I am playing. However, I should point out that most of the time I have been playing Traditional Jazz (Dixieland) where the chords are not complex anyway. But I would not dream of reinterpreting chords when improvising in a big band setting.
I really am very interested in what the pros and teachers have to say about this.