Isn't recording your chosen style chord progression into a midi song file on the your Tyros 5 and then using Song Position Markers on playback essentially the same thing as the Korg chord sequencer?

You would end up with the options of four convenient chord sequence loops (SP1, SP2, SP3, SP4) that you chose on the fly, freeing up your two hands to practice whatever you want.

Can easily be synced with any Tyros 5 style with sync start, including multipads on top of the chord sequences (SP1-SP2). Once synced, the chord sequence with follow the tempo changes of the style play.

Very dynamic control over your chord sequences, plus you can activate one the 4 loops on-the-fly, essentially generating access to four separate chord sequences.

Style Bass Conversion and manual bass control on the Tyros 5 can be setup within your style play and split point options while you create your chord sequence midi song file before you setup and enter song position markers.

Marcus