Over 100 Miles On Empty !

I bought my '06 Honda Civic Hybrid in Jan '06. I enjoyed the challenge of getting good mileage, and by June I had three tanks that were over 600 miles to a tank. I was surprized that I still had 1-2 gallons in the tank when I filled up. The next tank where I went on a few longer trips - I was showing over 60 MPG on the trip odometer (most hybrids have two trip meters to show your MPG). I decided to go for over 700 miles on a tank. I bought a 1 gallon plastic gas can for the trunk. My gas light came on at about 540 miles with 2 small bars on the fuel gage. My mileage was 565 with one bar left, and 585 miles with no bars left on the fuel gage. I figured it would be close! I drove the car an additional 116 miles with the tank on empty !!! My total was 701 miles for the tank. The trip odometer showed about 60.8 MPG - BUT my calculated MPG was 62.3 MPG. I used 11.2 gallons of gas on the tank, so I still had 1.2 gallons left in the tank. If the owner's manuel is correct, I could have gone 72 more miles on empty. My lifetime MPG is 52.9 MPG. I live near Buffalo, NY with the snow & cold. I am very pleased with my hybrid and I hope to buy a plug-in hybrid for my next car.