Nice write up! I agree with the other replies, we need to see more reviews like that.
Based on what I've seen from my readouts, your actual calcs are so much closer than mine are - compared to the readout. I'm curious what calcs are being done internally since they seem to be all over the place. It seems that we are both enjoying a roughly 10% increase in MPG, but like you I want to see a full tank with the same driving habits to make the real determination.