Sound switching is actually programmed in the 4X. I can't exactly remember the scenario.
I think as a person progresses through the variations of styles 1-4, the keyboard sets or sounds automatically change.
But I also remember that when this happens, the sound choices show at the bottom of the screen and all I do is hit the sound I want if I don't like what is chosen automatically.
Like I said, I can't exactly remember the scenario in which this happens.
PA 4X, S970, DGX650, JBL Eon One, Space Station V.3, Yamaha DXR10