What are you playing? It makes a difference.
Gordon writes for tournaments and assumes knowledgeable players who know that early position raises represent a smaller range of hands = stronger hands. Harrington's tournament book was written earlier and feels that you should get value for these stronger hands in order to make people pay more to call you with the stronger hands. He's carried that forward to his cash book, apparently. I have the first two but didn't find too much useful there so I don't recall.
If you're playing tournaments against knowledgeable players then Gordon's idea is fine, but otherwise, and in cash games where stacks are deeper, I'd go with more from early, less from late. But keep in mind that the sizing should also take into account your opposition. If you have a bad player who is likely to call with crap no matter what you raise, raise more. If you have an aggressive player or a short stack behind you who's likely to 3 bet, raise less.
Or, go the simple route and raise the same all the time, until all the stacks get short in a tournament, and then start cutting down the size regardless of position.