even though it's no use to further discuss this now (except with the responsible nokians):
from a consumer's POV, you'd have to count

N800: initial OS2007 + 2 = OS2007, OS2008, Maemo5
N810: initial OS2008 +2 = OS2008, Maemo5, Maemo6

You count based on the official marketing names that are made for communication towards the end user (OS2008), not based on internal codenames or dot-releases (Chinook, Diablo) you wouldn't expect end users to know about.


OTOH, there's some evidence that they had plans to keep this promise when it was made. - even more, i have to admit that maemo-nokians are treating me waaay better than their S60-counterparts. My S60 phone has unbelievable bugs and the one and only (and most probably last) firmware update it ever received didn't fix any of them, nor did it introduce new features. i also have no way to submit and track bugs, get feedback etc.... they're just zombie-esque in the S60 offices.
while part of this zombie tradition might still burden the maemo development, they got rid of most of it and seem pretty much alive and human.