Did you use cruise control too Dave?
I had a '03 Prius. It got about 48 MPG when the weather was warm, about 42 in the winter. NO BALLS whatsoever.
But on the highway with the cruise set at 75 it was reading over 55 MPG, and going through town with the cruise set at 35 it was reading 99.9 MPG (running on pure electricity).
Sounds great, right? I never realized how much I hated that car until I got my '09 Corolla.
Smoother ride, better handling, way more power, and I'm getting over 30 MPG. Plus the car was built in America. Plus I won't have to shell out $4,000 to replace the hybrid system.
Anyway, my point was that cruise control does make a noticeable difference in your mileage.