HHT can be deceiving, on a coarse stone you will have sawtooth edges that can pass a HHT test but are terrible to shave with. Same with the mirror edge, it looks very nice but doesn't always mean a perfect edge. If I use a Coticule and CrOx, I'll have a REALLY nice edge but probably not mirrored. My best tests are actually shaving or the arm/leg hair test where you are just removing the tips of the hair.