Some, but very few IME are comparable to 10-12K ish levels. I have had 5 different cotis and only 1 is near (but not quite) an Escher. What may happen with some cotis, is that they smooth out any harshness from a Nani 12k, and although I do not have one myself, I have felt the edge of a 12K and liked it alot, so theres probably little point.

IIRC I have read Lynn say few stones including Eschers beat 12K Nani, or something along those lines, do not quote me exactly!

Bottom line, I cant imagine many cotis would ameliorate a Nani 12Ks edge, but thats only my opinion, others I am sure differ!