I consider, in my own terminology, the Shock to be a neutral driver, much like I do the Volt. If I get a good shot with my Shock (meaning no OAT, wrist angle problems, etc.) It has noticeable turn but fades back more or less nonlinear with my release point. My Volts have very little turn,especially when I throw them, and they generally also fade back more or less to the release point, if not a little to the left. The Volts fade is more forward and less drastic.
As opposed to the Amp, which I consider to be "true" understable...meaning it has a good amount of turn and ahem it fades it is still to the right of my release point.
Whereas my fresh Teebirds, which I consider overstable for my skill level, ride straight and finish to the left of my release point, usually significantly so. These may not be the correct terminologies, but it works for my brain, I guess.
I'm not upset with the Shock by any means. I like it and I can actually carve lines with it, which is something Ive always had trouble with, even with understable discs. I just think their description was a bit off. Saying.g it is "neitral-stable" while maybe not by-the-book correct, is a much more accurate description IMO.