The main issue with WiiWare/VC numbers is that (and DKII or others can correct me), is that there's no way to really validate much of anything by Nintendo, Capcom, or anyone else.
For that matter, Capcom may not even know what the real number is themselves.
XBLA numbers aren't that way though, ours are pretty much the industry standard at this point outside of the piecemeal numbers that MS gives developers and the public.
FYI: Mega Man 9 did 24,000 on XBLA in 3 days...Much lower than WiiWare. So I guess the question turns to what the validation methods for WW games are.
The best comparison would be for a user to check leaderboards for Mega Man 9 on both the XBLA, PSN and WiiWare version and extrapolate from there, using the XBLA Leaderboards and unit sales from there to draw a close comparison.
Back from the dead, I'm afraid.
