Some interesting points of view here. I haven't been following the show nearly long enough to have any input but I do agree with some of the stuff said about the writing.
Well couldn't a "cycle" just refer to one body's "life"? I'm not all up on my Doctor lingo, but that's a pretty obvious interpretation to me.
But he says regeneration cycle; Cycle meaning multiple events and Regeneration being the event.
Please don't think I'm seriously worried about this, but I must point out that is not the only way to define the word "cycle."
For instance, the dictionary on my laptop has a whole list of definitions, and the first two lines are:
-A series of events that are regularly repeated in the same order
-The period of time taken to complete a single sequence of such events
So a regeneration cycle could refer to a series of regenerations, but it could also refer to the span of one regeneration. Ya dig?
Like snowdog said, it doesn't really matter because they will always find a way around the "rules" to keep The Doctor around, I'm just saying it's jumping to conclusions to assume that he definitely has 12 more.