His balancing machine is the standard center hole.
As mentioned earlier, this could be the root of your problem. You are not locating the wheel on your car using this center hole because the center hole is larger than the hub of your car. This is why the recommended balance procedure is called "stud centric" because you are locating the wheel by the taper on the lug nuts.
It can't be helped when the wheels are not located by the same method as mounted on the balancing machine.
All you need to do is to look and see if there is a gap between the center hole and the hub to determine the balance method.