If by "CEV" you mean the mean reflectively-consistent utility function of all living humans... then yes, this is most likely true, and I consider it a major flaw of average-utilitarianism for FAI. Why so major? Because any decent science-fiction fan can invent three ways to deal with the mutual incompatibility of some people with some other people that doesn't involve just taking an average and punishing the unusual, off the top of his head, and so can most moral theorists other than average-utilitarians.