Ryan Grim, a writer for Huffington Post, has documented a number of instances in which Dubya left an impression that he had witnessed a particular meeting recited in the book while pirating these supposed presidential moments from other writers' accounts. (Full disclosure: I have not read the book, nor do I intend to.)
Who knows? Maybe he believes what he wrote was part of his personal experiences as president. Ronald Reagan, the conservatives' Master of the Universe, had some of these same memory lapses(?) . As a projected war hero even though he never drifted far from Hollywood, Reagan drifted in other ways, citing war experiences that were actually created on a movie set rather than a live battlefield - and apparently unaware of the difference.