Yamaha CS80

Hi, I was wondering if anyone knew more about the following mod: 
http://www.matrixsynth.com/CS60mod.gif.  The 8/4 switch changes it 
to a 4 voice synth with 2 OSCs per voice.  The other switches seem 
to allow some sort of hold function; if you have one switched down 
you can play a note a few times and it will hold so you can play 
along on other synths.  Unfortunately if you try to play along on 
the CS60 itself, the note being held will eventually be replaced 
with another note you played - the magic number of notes to change 
the held note seems to me 3 or 4 notes with 4 more often.  It's 
really odd.  Twisting any of the tune knobs next to them will adjust 
the tuning of the note.  The tune knob next to the 8/4 switch seems 
to offset the tuning of the OSCs until they come back an octave or 
so higher, it's an interesting effect.  The other knobs seems to 
affect tunning as you play as well.  They have slightly different 
effects on tuning as if the right knob has more of an effect on the 
right of the keyboard while the center knob has more of an effect on 
the left, however both affect the entire range with the switches off 
while only their respective range with the switch on and the note 
held.  It's odd.  Note that the two center switches have a label of 
AUX.  I still need to experiment with all of this.  Just curious if 
someone out there knows exactly what this mod is supposed to do 
other than the obvious doubling of voices.  I feel like I'm staring 
through a fence that looks focused but a little off only to find 
that my persepective was off and the fence is actually further away 
(that stereograph effect).  Also, there is a 1/4" CV and Trig on the 
back.  One of my guesses is that these are ins so you can trigger it 
from a sequencer and play with the switches and knobs.  Kind of like 
you would with the individual voices of a Mono/Poly.