Froome was more than 2 minutes faster than predicted by pvam and 10 seconds faster than dpvam at the end of a 240 km stage ridden faster than the fastest predicted avg speed.
There's no set-in-stone, magical limit (6 W/kg) that can be applied to any performance. Why is it so f-in hard for people to put an estimated W/kg in context? You see this in the replies to vetooo's estimates. 6.1 for 20 minutes at low altitude? "Incredible!" 5.9 for 50 minutes on the Ventoux? "Below 6, not suspicious at all!"
Unbelievable!