Vito tried to get permission from the commission to kill costello a few times before and they would'nt give it, so he tried to kill him against thier will and nothing happened to him, from mu understanding he also killed anastasia without thier permission and still, nothing happenned
Frank Costello was a member of the Commission, so if Vito had asked permission to kill him then Costello would have had a legitimite reason to kill Genovese instead, with the Commission's approval, so I doubt it.
