The most important part of the post:

> This is a draft of a chapter for a book I am working on... My conclusions are pretty dramatic and I want to know if they are, for some reason, wildly wrong.

I am familiar with the author; he's genuine about wanting feedback. Some of the comments here are likewise genuine, but I worry that other readers here are like this fellow:

> The obvious answer is that the inconsistency is in bad faith, to fudge the numbers into fitting the author's preferred narrative.

You want "bad faith," try assuming the author's plea for feedback is dishonest.