It's not vague at all, so there isn't really room for interpretation. The question asked if you would be able to change party members, and the answer was that you can, but then you can't after the first act.
Maybe we're missing something because I can't see how it could be taken any other way as well, but who knows, apparently up can be down if you really don't want it to be up. this topic appears to be a black hole though, so I'm going to bow out here and keep my sanity
