Doc-Z,

I don't play many jazz chordings, but I have had a similar problem to yours, since I like to play riffs with left hand to augment the right hand parts and the accompaniment. I own and like Roland G-70.

I think the one approach you may try is to set keyboard into a split mode, and select the same tone (e.g. piano) for both upper and lower part. Also set chord recognition to Pianist. I think this may work better for you - the Pianist mode changes chords when you press 3 notes (or more) simultaneously. When it scans over the entire keyboard, it is very likely to detect 3 notes at once, and switch chord when you don't want it to. Scanning the lower part of the keyboard only, it will more likely hold the chords until you play another chord with your left hand.

I don't know that this will work for your style of playing, but it is worth a try.

Good luck,
Alex