http://energy.gov/sites/prod/files/2...enberg_2-b.pdf
Happened across this on different site. Page 5 they note 18.5% mpg loss from E10 to E85 almost exactly what I've experience with the 2 FFV I've owned.
It seems that Mercedes wants to increase the amount of ethanol per gallon to get a higher octane fuel.
Little more reading on Tier 3 fuels. And where image came from.
http://energy.gov/sites/prod/files/2...omass_2014.pdf