Anybody can come up with a good reason for anything
I don't think that Bush is so dumb that he would appoint somebody who couldn't think of a public reason for something that had a different, private reason. If you've been in the business world at all, or you've read the financial pages of the newspaper, you've heard a few "pursuing other opportunities" stories. Sometimes they are true. Sometimes not.
The large number looks odd, is all. Cripes, Tom, I'm not campaigning [I leave that sort of thing to you]. I just thought somebody around here might have heard something.