You're right. There will be the usual extra fee (something like €15 for each of the two guests*). It was originally included with the membership but then a couple of years ago the ACO introduced a 'lesser' membership, something like €60 instead of the €105 (or whatever it was). Now you buy your lesser membership and have to pay extra for the special area(s). I think that's right anyway, but I stand to be corrected.
(*I'm pretty sure that the guests don't have to pay as much as €46, but, knowing the ACO, they could well decide that....
).