WOW, WOW, WOW....so I spent a little time working with chord sequencer on vA2....
You can select a style, use chord seq. to do a complete arrangement from intro to ending.
EASY.
All chords AND style section changes are put in using the MIDI keyboard for chords & the mouse to select sections.

The....play the song & ADD as much left hand counter melodies or just chords (pads, strings...anything of course) as the arrangement plays live.

For the type of music I like to play this is going to be coooool!

There is also a RIFF function...and I have not looked at it yet.