More probably they figure (as does pittipat) that the number doesn't mean that much to most people. It does, however, to me. I prefer the correct figure but I klnow you guys can't even spell 29.87%.LOL! So when expatpat says 30% he's trying to fool people, but when the AFT says 30% "they just got tired"!
You'd prefer a lie like you give, perhaps, nightie???