its all down to contact patch of the tyre when on lock.

the more camber you run the more angle you will be on when the max contact patch is being used.

the wheels when on lock tend to want to be on max contact patch. ie if you are running modded hubs etc for crazy lock and run stupid amounts of camber the car will naturally want to go to full lock and not many people have the ability to drive a car on full lock all of the time, you want it set so its about 3/4 of the angle which for me is 4 degrees