Correct, but that just shows why the American style is so confusing. That we have to have an exception for more meaningful punctuation marks just serves to confuse, and emphasizes just how bad the default is.
I didn't even realize that periods were an exception. (as an American) I've always preserved the original quote for all three forms of punctuation, and put a sentence-ender only if there isn't one inside the quote. I'd bet most americans do the same, style guides be damned. IMO, it's also totally crazy to export a punctuation mark out of the quote always.
True, you really only have to worry about it if you're writing or editing for a teacher or publisher who wants you to adhere to some specific style. The real annoying thing for me (as an American) was having different teachers teach different things in school. (Same with double spaces between sentences in typing and the oxford comma.) At least when the teacher used a style guide, there was a source of consistency I could turn to, even if I disagreed with them.
