He had enough gap, that a heavier bike wouldn't be a problem.He was using the Y1Rs on Hautacam where he had a 1'17" gap.
Yes, the V5RS is a much better choice for the cobbles, but I still don't understand why he didn't change to the Y1RS for the Ardennes and for the Dauphiné.... if it's a better bike...
This will all become clear after the Tour. If he likes the bike, he will continue to use it in every situation.