Kind of funny. But it does make some sense. When the DLC was originally positioned it was simply announced as 360 exclusive for an unknown period of time, and made for some nice additional marketing next to the big MW2 bundles for 360 in US and elsewhere.
Now that the reality would appear to be irrelevant doesn't matter. I image MS simply wanted the perception that 360 had the bundles, timed DLC and was the place to play MW2 online during November and December.
I wonder though, if true would this be the shortest period of exclusivity ever? I'd love to know how much (assuming any) money was paid to secure this
I do loathe this whole timed DLC nonsense though.
Try to be reasonable... its easier than you think...