Petrol consumption not as good within the first 2000 miles?

When I picked up the car, I was told by the dealer to expect to refuel the car a little more often before the car is properly " run in ". Before this time the car will use more fuel and will not be as economical as it should. I thought this made sense. The dealer said it won't be a massive difference, if at all noticeable.
However I am shocked that the car has only done 50 miles more in this typical (journey wise) month then my old 03 1.4 corsa did in a month. The trips have been similar. My audi is also a 1.4 but also has a larger Tank so that alone should increase the amount- the fact that there is more fuel.
I really hope that I do infact see a big difference after it is run in and is much more economical. One of the reasons I went for the a3.
Has anybody noticed any changes or know anything regarding this subject?

I have pretty much been on Eco mode. Auto sometimes. My routes don't require a lot of speed.