Superdata is only good for giving numbers that are within a ballpark, the only problem is that the ballpark is so big that the numbers are obvious.
PS4 - We know that it was at 53.4 million at the end of the year. This suggest that Superdata are already off with their estimations by like half a million at least.
Wii U - It had shipped 13.36 million by the end of september, so their Wii U number is off by like 900k, which is actually astoundingly bad
XBO - Given that we have limited access to XBO numbers, there's nothing glaringly obvious that's wrong with the number, but it's something that any semi-sales savy user could've guessed anyway.
TL;DR Superdata isn't accurate enough for these numbers to mean anything at all.