E15 vs E10 Gas Mileage (No More E15 for me)

Consider the math.....
Let's say you have 20 gallons of e10 in your tacoma....e10 is 10% ethanol, meaning you 18 gallons of unleaded gasoline + 2 gallons of ethanol. If you used e15 you would then have 17 gallons of gas + 3 gallons of ethanol. The question is does that 1 extra gallon of ethanol make a significant difference in a Tacoma? I doubt that it does. Would I use e15 in an 4 stroke outboard motor? Absolutely NOT!

 

Waitttt so no one else plays around with filling the tank up 93 oct and the last 2-5 gallons with e85 = to make e-15e-25 ish fuel ? Using a e85 app calculator?? It’s a HOT mix I don’t do it anymore $$$$$$$$ 87 oct will do lol