Ok, so this is a bit misleading. The 79.8mpg IS correct, but the trip is a short 2.5mi. (the 20.7 instant mpg is from entering my driveway...)
Even though the overall elevation change on the way home is +113ft, I only had the engine on for about 45sec. total.
Much EOC!
I'm happy with it. Normally, I only get about 55-65mpg on the way home.