Hi! Been lurking for a while, at least occasionally.
Had to create a new account to post, and had some trouble--it seemed that it was cached badly, maybe because scripting was disabled when I first hit "register"? Clearing the cache fixed it, though.
Agree with everything but:
If you look in an old enough style guide (the current standard is as you say), it will say to use an apostrophe when you pluralize an acronym. Wikipedia agrees.