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See you can have a rotor that has 0.002 runout but if your hub has a spot where's it's 0.002 or more your total runout for the rotor is now 0.004 or more. It's called specification stacking.
I'm tempted to go through my back copies of "Brake & Front End", because I know I've read about total runout, tolerance stacking, and comebacks. Not all that long ago, either.