I found several TK flights (one ways) on ITA which appear to be O class. Previously O (and A) were comfort, which no longer exists on their planes.
But O still appears in the earning chart at http://www.new-milesandsmiles.com/index_en.html , and as being "comfort" and earning 135%...

So.. will flying economy O still earn 135%? If not, then how much?