Djordan, you listed examples where 4 ball wear test were conducted with gear oils, hydraulic fluids as well as compressor oils. None of your examples were an engine oil being tested.
Amsoil makes a good engine lube.. but the dubious and selective use of this test raises questions of integrity of the marketer that any objective informed observer can pick up on. I would not hesitate to use the product but the 4 ball wear test has little to do with that decision.