Look, here's the problem with converting existing MIDI files in a nutshell...

The file that needs to be used in a style cannot have ANY changes in it. However long the variation loop is for, that's how long the pattern must go on for without any chord changes...

Best of luck finding ANY MIDI files with no changes, without passing notes in the bassline or comping parts, and with four different sections with all the above that are usable as a building structure to make a usable style. From what I can make out, most of these lousy 'MIDI to Style' converter programs try to do this task automatically, usually to poor results. It is a VERY complex task, analyzing chord changes, and extrapolating what they WOULD be playing if no chord change had occurred. Beyond the scope of software, IMO.

This is a task best done by humans (and well trained ones, at that!), not left to some automatic process.

Prepare up the style divisions yourself, make sure that likely chord change boundaries don't have passing notes on them, prepare up alternative variations for minor modes, sevenths, diminished (whatever your arranger allows), prepare up major and minor intros and endings, and than import them to your style creator section of your arranger (or the 'blank slate' programs that the manufacturer provides), and note CAREFULLY which bar #'s are which divisions, and go from there...

That will lead to a FAR more successful conversion than leaving it up to any automatic process...
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An arranger is just a tool. What matters is what you build with it..!