Do you wipe your ball off? This is the first that I have heard of the Spec cover lane shinning really fast. Everyone else that I have seen use this ball, say the complete opposite, that it doesn't lane shine like other Storm balls. After the first shot or two, it's very stable and predictable.

Yeah I use a shammy after every shot. Soon as it shines it gets quite inconsistent.

Without actually seeing it go down the lane, it sounds like what you may need is a touch more surface, so when it "lane shines", it is closer to what you are looking for.

Anything that comes sanded is going to lane shine or be polished by the lane, and the rougher the surface is to begin with, the faster it's going to shine, that's just physics.  As far as them getting inconsistent, that's new to me, but of course I like most stuff with lane shine on it and I think something that ISN'T debatable though is that this cover blends wet/dry better than anything else out there, so inconsistent is the last word I'd use to describe the Prime or Pro Motion.  Maybe sometimes slow, flat, smooth, or lazy, but definitely not inconsistent.  It just sounds like you need something with more shape built into the ball in the first place, you have to shape the Prime and Pro Motion because they aren't going to do it themselves.