What did Dr. Diff say when you contacted him? He has parts made off shore (China) and sometimes the specs aren't exact. He quit offering the Eaton Tru Trac third members for this very reasosn.
Definitely curious about this as well, Cass is usually very helpful about this sort of thing.
That said, those are aftermarket rallye wheels, not originals, and the aftermarket rallye wheels have a pretty established history of not clearing certain brakes.