If you have a better idea of timing solves that fast, I'd love to hear it! Stackmat is pretty good in practice for determining how long a solve takes in a way that is unbiased and not affected by human error, but I agree, having to pick up the puzzle is an imperfection. If we could, it'd be nice to film solves with a high-speed camera - say, 100fps or more - and count the number of frames between the time the cube starts being turned and the "end of the solve" (let's say, the time when the cube is <45 degrees from the solved state). But that's not really plausible right now when we can't even get all WRs on film.