Don't you think the "port charges" referred to in the "generic" disclosure statement may apply when booking a non-DCL cruise using points? I don't know if we still have that option (since I haven't really considered it), but there was a time when we could use our points for other cruise lines.
I'm bet they still offer the Holland America Alaska cruise -- makes sense that that's the port charges they're referring to, if they're not talking about the DCL port charges.