That happens when I add a car too, When I add a top speed, the Mph is ALWAYS either 1 or 2Mph slower then what I listed, So I usually go up 1 or 2Mph when adding a car. Its actually ALWAYS been like that as far as I can remember, Or it could just be my system.
Whilst it is extremely heavy, I spent the day in one yesterday and was pleasantly surprised that it doesn't handle like a boat. Especially in sport dynamic mode. Its like having your living room in a rocket ship. it was getting a hilarious fuel consumption figure of 40L/100km in the city though.
This Bentley is too heavy to be a high performance car, especially after I've read a reported about Continental GT3 concept based on this Speed model, where was claimed that the curb weight is only 1350 kg! So if Bentley made a Continental Speed without all that options, which sometimes are useless, and used carbon fiber and light metals, it could have a curb weight approx 1750 kg or even a bit less! Then it would become a GT supercar by Bentley. I've read also that GT3 is able to accelerate to 100 kph in 3.2 s and the handle is much better. And imagine that road legal - it would become comparable maybe even to a Datsun GT-R!