User blog comment:Heg Oiu/An exact definition of level difficulty/@comment-16894369-20161008194251

Very interesting. I also realized that this is very similar to what I used to assess the difficulty by the number of tries, which is also influenced by the Virtually Guaranteed rate.

There used to be levels in the past that seem to be having a very low success rate (to a point where more than 200 tries are needed on average), and those are the one that were deserving Nearly Impossible. In general, I think it is necessary to limit the number of levels that are actually graded above Very Hard - which is what I'm currently trying to do right now for the levels beyond 1000.

Personally, I will be only looking for a level to be graded Nearly Impossible (according to the current Difficulty System) if there is a significant number of comments suggesting so. Even then, I will try to deny the rating to be here if even a mere 10% (excluding booster players) of players opposing it.