F1 2012 Single Player and Multiplayer Performance Difference

[Naparogus]

So I've conducted this little test.

Test1:
Circuit: Silverstone
Laps: 50% Race
Mode: Single Player
Car: McLaren
Laptimes in RACE: Constant low 1.34s and high 1.35s

Test2:
Mode: Online
Circuit: Silverstone
Laps: 50% Race
Car: Force India (Performance set to equal)
Laptimes in RACE: Mid 1.36s, can barely tough low 1.35s

I read in a post on this forum that all the equal car performance is of McLaren's. I cannot understand why is there such a deficit. I can say that I'm a pretty decent driver and have been doing league races. So consistency is not an issue here. If anyone can shed a light on this, it would be pretty helpful.