If you can give me a little more information, I'll see if I can think of something.
What's the name of the style you're using?
What tempo are you playing it at?
BIAB is definitely terrific software. While you are getting the hang of how it drives, there's a lot to be said for working in 3/4 or 4/4. That's my experience, at least.
It's very unusual have chord changes on 11 and 12 in 12/8 because 12/8 is really a 4-beat time signature where each beat is subdivided into 3 notes.
Please let me know the answer to the above questions and I'll see if I can workout anything.
Regards,
Noel