I don't know anything about the score you're referring to. However, just for the record, I have some jazz score written for trumpet and saxophone, along with backing tracks. Above the score they have chords called out. And all I can say is that they are definitely NOT playing the chords called out on the sheet music. When I try to play the chords they call out on the piano it sounds horrible. It's definitely not what they are actually playing for sure. And I've double-checked, triple-checked and quadruple-checked. I'm not making a mistake, the chords on the score are clearly wrong. Fortunately the trumpet and sax melody lines are correct. But I'm at a loss what to play behind them on the piano because the chords called out on the score are not working.
I also wonder about the following:
These score seem to be written out in Eb or Bb for Alto Sax and Trumpet respectively. I'm wondering if the chords they are calling out need to be transposed for piano? If the chords they are calling out on actually written out in Eb or Bb, then they would need to be transposed to concert C before they would make sense on a piano.
Disclaimer: I have no official education in music. So I don't know what the standard is for writing up jazz scores. All I know is that if I play the chords they call out it doesn't match the backing track at all. It's either a misprint, or some sort of transposition needs to be done to transpose these chords for piano in concert C.