I haven’t got a solid “tuning” either from my A4 to the SP, but I haven’t tried throughly either, I get caught up in how cools it sounds out of tune.
After going over the manual again, pg 52, I saw this
MIDDLE C sets the overall tuning of the pitch CV.
V/OCT sets the pitch width of the signal.
It seems to make more since now.
I just wanted to add that you got to check your momentary note settings on the Slim Phatty. At least that solved the problem for me. My Momentary Note was an E and so I could maybe tune the first note (C3), but when I adjusted the second note (C5) the first note was out of tune again. Made me crazy 
So I calibrated the whole Phatty, corrected the Momentary Note setting to C and voila everything worked perfectly.