Howling:Eleventh Doctor's Phone Call

In the episode "Deep Breath" Matt Smith's Doctor calls Clara with the twelfth doctor present. 11 remarks that he thinks he will regenerate soon and that 12 is also him or something close to this. The problem is that 11 thought he was out of regenerations as far back as "Let's Kill Hitler" or when he used regeneration energy to heal River Song's wrist in "Angels Take Manhattan".

1. How could he know he'll regenerate when he obviously didn't think he had any more and seemed ready to die at the end of the Christmas Special?

2. Matt Smith "looked" young during the phone call but thought his regeneration was close but obviously missed the mark by a few hundred years as he was very old looking at the end of the Christmas Special.

It makes it pretty obvious they are making it up as they go along, but are trying to fit it together.

Rayz