Had new tires put on an '05 Mercedes yesterday and watched the tech balance the wheels. After he had placed the weights on the two spots indicated he spun the wheel again to check balance and each time he got double Zeros for both weights. Don't know what the norm is, but I was impressed that he took the time to check his work. I have seen techs that don't do that and sometimes the wheel wasn't balanced right. I made sure he was rewarded for his work.