User blog comment:Kacj321/Skyrim Previews Jumbo Post 17/10/11/@comment-24.231.217.108-20111018210551/@comment-30303790-20111019033559

I think it's shortened because of the way its spoken, not because of the size of the increments.

For instance, I would say: rather than saying:
 * "Skyrim comes out on Novermber 11th"
 * "Skyrim comes out the 11th of November"

Though again, that might just be an American thing. Sometimes we just love over complicating things. . .oddly enough it could also because the extra "of" would be too hard.