I can't figure out that example at all but I believe it certainly must be a PiP sweet spot. I've now owned both a PiP and Volt - didn't use much gas before - filled up just twice a year in my PiP Now I use no gas in the Volt
^ I used to fill up the PIP every 2.5 weeks. I've filled the Volt one time since March (and still have 3 gal left in the tank)- I have 10.5K mi on the Volt.
Test drove both the volt and the PiP... Liked the all electric of the volt but found it much to cramped for my lifestyle. I am biased as my wife has a 2nd generation (2009) prius. Just bought a 2012 PiP advanced with 30,000( 18,000 miles ) drove it home 3200 k ( 2000 miles) average 4.5 liters / 100 k ( 50 mpg ) My commute to work is 16k ( 10 miles ) and can plug in at work so PiP works for me Sweet Ride!!