About 55miles? .. on track
I think I can get the gauge on the fuel consumption app to hit 1.4mpg!
economical I think when you consider how much fuel the space shuttle or a Saturn 5 Rocket burns..
In all seriousness though I have managed 346miles in my Classic Wagon STI, and that is fully laden with luggage, it was a slow drive though! average 65 odd! I would say your numbers are spot on, considering when your doing 70 your near that magic 3k rpm "I want to fuel for boost" mark on VF series turbo