Im australian, and a "couple of things" is some small number, like 2-4. Using it for exactly 2 seems like people are confusing it with 2 things that are coupled. Why not just say 2 if thats what you mean.
Why does English ever have synonyms? I'm not saying you're wrong, clearly (as a a Kiwi) I've been misinterpreting Aussie usage, but "there's already another way to say that" is pretty common.
Would you go so far as to say "there's a couple different ways to say that?" As an American, this sounds a little folksy but not that odd. And it wouldn't mean that there are exactly two ways to say something!