Mileage can drive you crazy!

OK, we've all seen posts where people get great mileage on the highway, but I've never thought it possible at "high" speed.

Yesterday, I and a friend went on a "survey trip" to check out the "Starland County Recreation site", with a stop in Airdrie and Didsbury. Total round trip distance 730 km. Filled up before I left, filled up this morning. 33 l used. That's 4.3 l/100km or 65.7 MPG imperial or 54.7 MPG US. I traveled at 103 km/hr for about half the trip on secondary highways, and 115 Km/hr the rest on the "ballistic expressway" that is the QE2. As I watched the cars readout tell me it was 4.3 I just mumbled "oh sure, yeah, right" (it has consistently been very optimistic in around town driving). But it was accurate! I fill till there is liquid fuel in the filler neck that I can see just above the "anti-siphon valve" so the fills were accurate. I used cruise whenever possible. And I didn't spare the "HP" when driving. Reasonably fast acceleration etc. I even passed cars when "necessary" to maintain the speed I was traveling. Also checked the speed readout (speedometer) with a GPS and it reads 2 km/hr high. Speed listed above corrected for that.

Oh, and I was tired afterwards, but not knocked out. The seat was comfortable the whole trip.

This car amazes me every time I drive it.

 

OK, so here's the thing that made me post.
Pearl (GII 2007 Prius) got around 4.7 l/100 km in similar driving, and in town around 4.5-4.6 l/100 km, just like she was supposed to.
Pearl S (GIII 2012 Prius) got the highway mileage as posted (4.3 l/100 km - and no, there was no wind involved). Around town she is getting 4.5 - 4.7 l/100 km. Now I'm willing to admit my driving -style- may have changed, BUT even Pearl S is -supposed- to get WORSE mileage at highway speeds.

I'm hoping for others to also post their results. Perhaps Prius are "evolving".