FADI! Those are GOOD numbers, not bad numbers!

Ethanol is not meant to improve MPG. We all expect MPG to go down... in most cases.... but how much down is the point of this study.

You appear to have replaced 30% of your gasoline with a partly renewable fuel.

We can't be sure that E70 even exists... just that the rules allow it to exist... right now, wholesale ethanol is about $2 a gallon, and gas is near $3 a gallon, so there is no financial incentive for stations to dilute the ethanol with gas. It is more likely the E85 was E85.

So 30% ethanol created a 0.8/43.1 or 2% loss in MPG ( compared to E10 ).

20% more ethanol created 2% less MPG.
That is a very, very positive result.

Now, it takes 3 gallons of gas to make 5 gallons of ethanol.
So volume gain is 66%.

But your car only use 2% more!

I'm very happy with your report.
If you are comfortable to continue using more ethanol, I think it will be a plus for the planet, as long as you don't need to drive ( much ) out of your way to get it.

30% ethanol in my FEH reduces my MPG by about 10%.
Your car seems to almost not care it is there!

-John