Basically, this disproves the theory that Lewis was happily sitting behind LEC. They just didn't really have the pace on the C2 due to overheating (presumably caused by the very, very hot temps for Silverstone). There's probably an element of LEC pushing harder to stay ahead (as Allison alluded to fuel saving in the second stint, but that may also be explained by that mapping issue Ferrari had).
Pleased they were able to really lean on the C1, but they will be in trouble in Hungary if they are unable to keep tyres in the window especially with softer tyres and warmer temps.
Also, Allison's comment on upgrades is clear that whatever will come at Zandvoort will be extremely minor. If it took Merc 4 months to come up with a few aero bits sprinkled around the middle of the car, I don't expect anything big then.