Chris A,

Thanks. I found the mixer lock which is found in general Midi as you said. I tried it and it works.

I love a happy ending

Have you tried switching OFF the GLOBAL button (in the middle, under the display). If this is switched ON, then a change of Style will revert to its GLOBAL setting. This is also true if you simply use the STOP/START button during playing.
Once you have all the instruments and volumes to your satisfaction, then SAVE as a new USER GLOBAL.

Mike,

There is no global button under the display. However, there is a mixer lock that worked.