Take the best 10 hero or zero runs by the pros and call that 100%. Make even 'A' class runs unobtainable on some of older CM's. Sounds legit right?
I paid no attention whatsoever to the HHF recalculation but math is one of my strong suits. Perhaps someone can explain what was fucked up about the recalculation?
If you didn't pay attention, that's because you're already a GM (so who cares) or more likely a 'B' class for life dumbass.