I’m pretty sure E-85 is 85% ethanol, not 15%.
You're right.
Here, we have the choice of E-85; E-30; and "regular gasoline"--10% ethanol added--. The numbers never come out 'right', though the more alky, the lower the price.
The other numbers don't come out 'right' either. When I can get REAL gas, the difference in milage is more along the lines of a 15-20% drop with 10% ethanol.
Even with a choice of having an E-85 vehicle, I wouldn't buy one: SUVs are dangerous enough when sober, let alone turning an alcoholic one lose on the streets!