It's the exact same wording for super-heavy vehicles, except that super-heavies are counted as stationary and stationary vehicles get to fire all of their weapons. I totally get where the 'each refers to the aforementioned two' side is coming from but I think it's splitting hairs over GW's newest installment of 'power creep'. We might not have a precedent set for it with Gargantuan Creatures not yet having more than two weapons at a time (not sure about any potential FW precedents set, I know they like their big models) but I just can't see GW releasing a model that has five weapons stock but can only fire two per turn.
EDIT: As a disclaimer that I'm sure you're aware of (but maybe not the casual reader), I don't play either of these armies and don't actually care one way or the other. I just like talking about this stuff :drinks: