2008 Odyssey first trip

I have a 2008 odyssey that was purchased about 2 months ago and I haven't been very far in it. We just returned from a week up the north coast and was very surprised at the performance and fuel economy. I drove via the cruise controll set at 5-10 kms over the limit going up and returned 7.6 litres per 100 for about 530kms (bit over half a tank)
Coming home it gave between 6.9 and 7.1 litres per 100 for half a tank of fuel for 510kms.
I thought it might be a little thirsty for weight of the car and a little under powered, but it was not.