I’ll bet you do.
What Forrestal ,p. 83, says is that Byrnes felt that the original Japanese response, and their “assumption” as to the prerogatives of the Emperor, might taken as receding from the “totality and severity of the Potsdam Declaration”. Forrestal’s comment was that he felt this could be “met by an affirmative statement on our part in which we could see to it that the language of surrender accorded fully with our intent and view”, in the Declaration.
And that is the structure of the reply. No one, in the Declaration or the response to the Japanese, which said that the Emperor would be subject to the occupation authority, made a mention of what would or would not happen to Hirohito, or the Throne, or, for that matter, the totality of the kokutai, save that it would be determined by the will of the Japanese people.
When we decided to allow that, of course.
You can read Stimson’s diary entry on that meeting, Kort/COLUMBIA GUIDE TO HIROSHIMA AND THE BOMB, p.p 235-236.
Now get back to reading Bix.
It helps understanding, to have the books.