Sorry I missed this. This sounds very very similar to my experience, and in fact only within the past couple of weeks have I been getting scratch free (or, as you describe, very very shallow scratches) finishes from the 16k. I don't have a DMT 600, but the DMT 325 I now use seems to do the trick, I start by lapping with some pressure, and let up to very light pressure. This leaves a very smooth surface. I'm wondering if the lapping film I used was actually leaving aggressive scratches that in turn gouged my razors?
I still cringe thinking about the finish it was leaving after I lapped with the Norton 600 grit sandpaper.. Yikes. Oh well, anyone with a 16k reading this thread can hopefully avoid this issue.