OK - do you have a link to a source for that information so I can add it to my pile? I don't mean to be a pedant, but given that it was Simpson who reported McMurdo Station to be 27 miles from the waypoint, does that mean he flew down the Sound, made a left turn at the waypoint's longitude and flew overhead? I realise the visibility was a lot better when he made the trip, so it's possible.
However, even if true, that doesn't really change anything as far as I'm concerned. Simpson was flying the "false" track and as such would have been able to descend safely to 2,000ft at the same longitude Collins did with no negative repercussions. The crux of the matter for me is that both Collins and Simpson had the same briefing materials, but only Collins flew the route with the unannounced changed waypoint. Thus the briefing (including the verbal dispensation in particular) would have been perfectly safe for Simpson, but Collins was placed in considerable danger by operating to the same parameters and restrictions.