G2Prius : Absolute maximum mpg @ 65 mph and beyond ?

I planned to aeromod a 2008 Prius with a full length boattail, smooth underbody, wheel skirts front and rear, reshaped nose, and removed mirrors and rear wiper / antenna.
However, after finding out more about how the hybrid system works, I have given up on the idea.
According to A.I. , the Prius does not allow the car to take advantage of aerodynamic modifications to the degree that other cars do.
A.I. estimates a maximum of less than 60 mpg at 65 mph even with extreme aeromodding.

So I'd like to ask what is the absolute maximum real time mpg you have seen from a G2 Prius at 65 mph and over ?