You might be able to get some of the benefit with an external sequencer or connecting up a 2nd keyboard. I have always wanted to try this experiment:

Before the live session, make a recording of only the chord notes (what Roland used to call the NTA "Note to Arranger") played in their proper timing and duration. Save this as a MIDI file. Now connect the 2 KBs together. Set up the primary arranger's chord recognition engine to read chords from the incoming MIDI channel, but not to actually sound the notes. (I know PSR-3000 can do this, others can as well.)

Set the Sync Start and play the MIDI file on the 2nd keyboard. The chord notes stored in the MIDI should drive properly timed chord changes in the style, but your LH will be free to work the bender, vary the tempo (on the MIDI player), turn style channels off and on, fills, variations, even manual bass. Yes you do have to record the MIDI entirely in advance, but using banked chord notes to drive the style allows the player to be a lot more spontaneous than just playing over a backing made by step recording.

I have the PSR-3000 and it allows you to step-record the chords ahead of time. But once you "expand" the step recording, you are just playing RH over a midi file ("song")- you can't use the style fills, variations, etc. This is boring! IMO Yamaha's implementation of the "Chord" tab is half-baked. I kept waiting for this feature to be fleshed out in an OS update but now we are at v1.80 and no joy.

If anybody tries this and it works, I would love to hear. -Ted