I think there is the possibility that someone else looking at all the documentation might have a difference of opinion from Ted on whether or not he was a citizen at birth.
I think there is the possibility that Cruz is making a statement of fact, based on one interpretation of events, the one which he finds most favorable.
I think he's doing a lot less than he could to get the question of his eligibility resolved. Up to now, he seems to be relying on people in the press and alternative media presenting his case, all of whom are relying on speculation of what the documents would actually show.
I think some people will never be satisfied, and will always have one more question, just need one more document...
Cheers!