I have own PIP FOR OVER 3 MONTHS , MANY DAYS GOING DOWN AND UPHILL ON 8.5 COMMUTE I AM GETTING THAT MAGIC 999 MPG. I HAVE MY LOWER GRILL BLOCKED WITH PIPE INSULLATION AND I AM USING BOTH EV AND ECO AND IT SEEMS TO SURPRESS THE ICE FROM TURNING, ON, AND IF I KEEP MY SPEED BELOW 60MPH I CAN GO BACK AND FORTH AT THE MAGIC 999 MPG. tHE BIG THING IS THAT I CAN CHARGE MY PRIUS AT WORK JIM COLEMAN TOYOTA IN BETHESDA, MD WHERE I AM THE HYBRID SPECIALIST. WONDERING HOW MUCH BETTER I CAN DO WHEN THE WEATHER IS WARMER. ALL TOTAL WITH LONGER TRIPS ABOUT 108 MPG AND 32 GALLONS OF GAS
Doesn't it feel great to consistently see 999 mpg? My daily work commute is similar to yours except mine is pretty much flat surfaces.