I just noticed that an 8.375 BBS pressed deck I got has off center concave, meaning, more concave on one side. I'm not sure how that mistake can be made, but I've seen it a few times over the years. I didn't notice it on this deck until I stood on it and I could actually feel the difference under my foot. Then I looked, and sure enough, the concave isn't centered on the deck. Glad it's not one I intended to ride.