Thanks for the reply, I stopped after 100m after the finish line... But if I finished the VE after the finish line I don't understand why I should be penalised anyway.Did you continue driving the cooldown lap after crossing the finish line? Maybe that's why you ran out of VE.
VE level has no impact on performance, only on pit-stop time, so unless you have to make a pit-stop there's no advantage to lowering it.
Adjust the fuel ratio if you think you need less fuel.