From my experience a higher powered engine actually ends up being more efficient because you're not wringing it's neck all day long to try and keep up with the traffic.
I can imagine this isn't the case in rural areas when you can just pootle at your own pace but round here everyone is always in a hurry and you often have to give it some to get into that little gap in the traffic.
I would say not, mixed driving my 199 get half the miles my 102 got