I have the data and when it's complete I'll share it. I was trying to get a rough explanation out before finalizing. Also, it is simple to find out the VIT of the mob when your STR starts to do little to no effect against it. You can do this by slowly lowering it til you see diminishing results.
This is simple stuff. You don't need to wait for developer confirmation when you have the capacity to test it yourself. It is incredibly surprising to me how they are not able to explain their own workings of STR and Attack Power, but the community can.