Thank you, this helps very much. I didn't realize clicking the fare class would show that info. The greasemonkey script is pretty useful.

Unfortunately now I have only confirmed what I suspected...despite first being almost completely empty there are no upgradeable flights from IAH to NRT/ICN with a gpu, at least not when I travel. I've only managed to mileage upgrade once out of more than 30 attempts, so this isn't much of a surprise.