I have the Navi on my 2007 HiHy, so I'm not totally sure how your FE displays work. However, you would not see that kind of MPG jump in your lifetime FE. The math just doesn't work. Maybe somebody else can answer this more definitively, but maybe the FE automatically resets after so many miles.

These vehicles can get decent fuel economy. There are some tips in this thread:
http://www.greenhybrid.com/discuss/f...hlander-14849/