Y to perform 2 weeks before release Cheryl? The video is out for a while, the song is not that new... perform on The Voice (Powerful as hell) and release at the same week. Don't get it... sorry.
I think they will bring the date forward, they just haven't announced it yet.
Though if she doesn't people will go to itunes and just pre-order it, and then it has another couple of weeks to build up more sales and then on the eventual release she will have massive first week sales.