My Dad received his iMac a few days ago and the first thing I noticed is that the entire screen has a yellow tint over it. The screen on my late 2011 15" MBP looks a lot better, without any yellow tint at all. Quite disappointed. Is this a return or do all 2013 21.5" iMacs have this yellow tint across the whole screen? When you compare my MBP along-side the iMac the difference is stunning.