the clock starts from when the sc deployed message comes up on the cars on board display. the time it has will be determined by its relative position on the track, each one is tracked by a gps anyway so that'll be used to give the time. It worked well in the test sessions last year. Hopefully now we wont have anymore repeats of the sinapore ferrari farce. My only concern is, this may decide a race far more than the old system. If your past the pit lane and the sc comes out your screwed, where as in the old system at least it was up to the pit crew to get you out quickly. I am glad its back to the old system, but I think you'll see a lot more people complaining the first time a driver loses out because they have to trundle back to the pits on a lap no faster than 2 minutes, while the guy infront may only have to do it in 90 seconds because he's crossed into sector 2 already.