Quote from ruksakSo, maybe I'm missing something? Perhaps the formula isn't considering something it should, or, perhaps it's considering something it shouldn't?
Aside from all the particulars, I'm not sure of the point? If one wishes to know what MP they are optimal for....well.....play the game and you'll find out. I don't need a "tool" to tell me if I'm having difficulty, so I'm thinking this tool needs something else to make it relevant.
I don't think the tool is suggesting what MP you character is capable of doing. Anyone with sufficient EHP and sustainable life regen setup can do max MP10 if they want too.
However, you can, doesn't mean you should. Be it legendary farming or demonic essence farming, sometime, downgrading a few MP will yield more effective result. Especially if you are planning to farm for long hours... instead of stressing yourself with constant repositioning and kiting from environment damage in higher difficulty, playing at lower MP is much more relax.