This is quite a powerful little program, Chas. I suspect the main reason you do not use Arranger styles is because they don't have enough "unpredictableness" (if that's a word ) and have too much repetition, especially for jazz and/or blues.

BIAB, even in its earliest versions, seems to have some sort of Artificial Intelligence and you are constantly delighted at the subtle changes that take place during (and are different for) each playback.

Actually, I'm surprised you haven't already exploited this relatively inexpensive and easy to use program...it would be awesome to play jazz organ over, and many of the Standards are already done for you...plus, you can easily transpose for practicing tunes in different keys, and the tunes can be edited to suit your own personal needs., i.e. you can thin out an arrangement so that it only has the very basics.

It certainly bears further investigation, if only for those great jazz/blues (and funk) styles.

Ian