Disklavier

Several XG voices have the designation "KSP" at the end of them.  KSP 
stands for "Key Scale Panning"--left to right, or right to left.  I 
certainly understand the concept of a voice panning from the left 
sound channel to the right sound channel as you move up the keyboard, 
but don't all the Disklavier voices do this?  Is this all an XG "KSP" 
voice designation means, or is there more involved? Is there anyone 
around who has studied the XG voice concepts thoroughly who can help 
me out here?

For more info go to:

http://www.yamaha.co.uk/xg/
download/docs/xgxtra6.pdf

Thanks,
Richard Wilson