You also have to fully work each grade of paper. IE: if you still have 400 scratches, 600 doesn't remove them. In fact, sometimes the higher grit will show scratches you thought were gone. The solution is to go back down and work back up.
For a working knife, you have plenty of polish on that blade. For really shiny metal, at some point you need some metal polish / rubbing compound / etc.
When polishing parts for my bike, I will usually finish with Mother's metal polish or use a good carnuba wax. This helps keep some of the shine once you are finished. For a knife, I would keep it oiled.
Good stuff. Thanks. I noticed that as I was sanding. I guess I'm a perfectionist so I worry about each little crevass where some black spots of the old epoxy were left behind and I want to sand out. I will eventually put some metal polish.