User blog comment:Saratje/PC release date explained - Skyrim: Dragonborn DLC/@comment-1992639-20121203173135/@comment-87.202.178.35-20121212134838

also another point that noone seems to have mentioned (my apologies if that's not true) "early 2013" is very obviously intentionally vague and can mean some date in january, it can mean some date in february and can even mean march (as in 1st quarter).

So theoretically speaking dragonborn could be released for pc/ps3 up to 4 months after the xbox release and still bethesda could claim "well we just said early 2013 and there it is, its still early 2013 even in March"