Oh, so I look dumb? Whatever. Having a ring there only makes sure that the radius from center of ring to center of wheel is the same on all four lugs. There still is an angle phi that exists between the center of the stud, the center of the hub and the center of the wheel until the lugnut is tightened, forcing phi --> 0. Can you see that? OK then, if one holds the wheel onto the hub, supporting from below as I have done on countless autocrosses, and then apply all four lugnuts, then torque them down in a diagonal fashion, a centering ring is simply unnecessary. QED.
