I thought that the loss through the chicanes was the suspension setup and the basic fact that the weight distribution was too much like an Autin Metro.
I think there were a number of factors at play, not least that the suspension was too fragile to cope with too much kerb being taken, and that the hybrid system wasn't working at all thus the front brakes were wearing out as they weren't being used to harvest energy as they should, and without the hybrid system they didn't have the extra energy to power out of corners at all.
I seem to remember that despite being the fastest car through the speed traps they were dropping something like 8 seconds from Tertre Rouge to Mulsanne Corner!