I think there has to be something else going on here. I've just heard again the line of "'the engineer accidentally had the fuel pump on 'drain', noticed it, and changed to 'fill', but there wasn't enough time to add on the amount already drained". What is the fill rate of these machines, still around 10l/sec?
I would assume that McLaren under normal circumstances would fill the car to have around 4l left after the qualifying lap, to allow for a slow down lap, a litre for checking and a little bit more for safety.
So, and these figures are perhaps plucked out of the air but not miles wide of the mark, this implies the error was spotted in at most half a second, and there wasn't a couple of seconds to correct it? I don't know what McLaren would be covering, but it just doesn't ring true.
As for the penalty, I overheard MB relaying a conversation with Charlie Whiting, saying (paraphrasing) a technical infringement = disqualification no matter what, so I guess it is the right penalty, but, surely it's (or should be) a sporting regulation, and so a wrong penalty has been applied?
Either way, McLaren have once more expanded the envelope of fuckwittery.