User blog comment:Saratje/PC release date explained - Skyrim: Dragonborn DLC/@comment-4269579-20121230031418/@comment-97.83.129.58-20130104034645

@DarthOrc Really it is microsoft who is in control over that. I'm sure bethesda would love to release this at the same time for all systems to make money sooner, except that microsoft would probably try to sue them for breach of contract.