Check the Castrol MSDS again. While we must remember that an MSDS is not a recipe, I see nothing in there indicating that this is a primarily Group III product, and I see indications that there is PAO in it, on top of all that.
And yes, companies can market a primarily PAO oil for $25 a jug, even up here. They can do it for half that yet again, if they really want to, and do so up here, as well. Just because boutiques think that PAO means $15 a quart doesn't mean that applies to everyone.