I have no experience with either stone: Norton or Chosera, but as far as I'm aware the difference in sharpness and polish between 8k and 10k is very minor. How you hone, the razor itself and the character of the stones are all arguably much larger variables which will have a far greater influence on the quality of your shave than the material difference between an 8k and 10k finish. So it could simply be the stones and the razor. In which case you might find your Chosera will be better for other razors. On the other hand it could be down to how you're honing with it, or a combination of the two. In which case practice with the Chosera may help.