After a friend of mine did some work regarding getting the exp on hit formula, we’ve resulted in two equations:

Hitting an npc with different damage values while the NPC retains a consistent value results in this:

y ~= 1.825x where y is exp gain and x is the damage.

The equation for hitting different leveled NPCs with the same damage value results in this:

y ~= 85log(z-7) + 75 where y is once again exp gain and z is the level of the NPC.

Now, the question is, how do you combine the two equations to get the exp gain, including both x and z? I don’t think you can set the two equations equal to one another, by the way.