Very low mpg on new vehicle

I just bought a new Tuscon Hybrid and very happy with it in terms of features. But when I went on my first road trip I was only getting 24 mpg, and this was eco mode and cruise practically the whole time.

I wondering if I should take it for service because that's almost like the hybrid system isn't working. I have heard of a break-in period. Should I drive it a couple thousand miles to see if it improves?

I have tried calling Hyundai service at my dealership, but it has been impossible to get anyone on the phone.