There are two things that spring to my mind here:
1) SAVE TO A DIFFERENT NAME. ie: Say you have chosen Piano Ballad from your SD Card of styles, you then change Right 1 and/or Right 2 to another instrument, for quickness, I would save it with another name such as Piano Ballad-2. (note the 2)This is a quick method if you are looking for That 'elusive' sound for a particular song.
2) When saving, go to Page 2 click on 'ALL OFF' at bottom right-hand corner of screen, which will put 'NO' in all the boxes, then click the arrows at the bottom of the screen against the part you want saved, in the example above this would be CURRENT PANEL OR PANEL MEMORY (if using more than one PM). Having made your choice, 'YES' will be shown alonside your choice. SAVE in the usual way to the new card You should now have the original styles saved but with the new changes.
The KN7000 default setting is to save in PERFORMANCE mode and like a PC it has to be told to change it's settings, otherwise it will always revert to that mode.
Hope this helps.
Audrey