calcualte monster damage on me?

While you raise an interesting point, the difference between that and a player's MATK is that a player has basic attack listed with the skills and a mob does not... unless you have another idea as to where this value could be found?

Well we know how the formula works going forward, so why don't we take the damage we receive from a mob and reverse the order in order to find the missing values. Then once we have those values we'll have some data to see if the missing value is unique constant Variable, a Exponential, or something else.