I don't think his coticule is tearing up the edge, I think we're seeing chips resulting from underlying issues. As far as the scratches go, the new ones made by the coticule seem to be ball park 8K, maybe a touch finer. So nothing wrong with that stone imo. Just the issues that present starting in the 4k photos.
Small tip for yours, and I thought this was kinda crazy until I tried it, burnish it. Make sure it's fairly flat and reasonably polished, then take a razor that needs work or something and just start doing laps. Mine took about 2,000 to stop seeing loads of metal swarf. Which is a good thing if you want it to finish. After that it kind of worked OK. Then I took it a step further and coated the stone with green chrome Ox and buffed the stuffing out of it with a dremel and a cloth wheel. Ever seen a coticule with a mirror shine? See post 53:
http://straightrazorpalace.com/honin...e-drink-6.html
Before that stone might - might - have been a 4k. Now it's a pretty decent finisher. I also found that it doesn't like shave lather or water, even if it's running. It likes a 50/50 blend of mineral oil and mineral spirits.