100 mpg--an artificial limit?

If you have a trip summary report that displays 99.9 MPG there is a simple way to calculate your actual MPG without a UltraGage. MPG = trip miles X price per gal paid on last fill-up / cost of trip. Example; 9.2 miles times $3.85 divided by .30 cost of trip = 118.06 MPG. The trip miles and cost of the trip can be found on the trip summary screen with ignition OFF. The gas per gal can be found on your settings screen. I have a pocket calculator in my Prius C2 to do the math. I have had trips as high as 133 MPG. My 133 MPG is a regular reading when I take often trips to the USMC base theater located 9.2 miles from my home. The reason for the consistent 133 MPG is the trip is mostly downhill. Using the Google Earth App I found a 1028 foot altitude difference traveled during the trip. Coming home the 1028 foot climb uphill gives me mostly a 54.2 MPG. I hope this helps those wondering the true MPG when they see 99.9 displayed!