they probably don't sell nearly as much E85 as they do regular gas so they've still got some older Ethanol in the tanks that they bought at a higher price. with the way the price of gas has been crashing lately, the two prices ended up the same.
also, i don't think the price of ethanol is going down like the price of gas.
in Fergus Falls, MN, 87 octane is right around $2.00, and E85 is something like $1.69 or so.
look at it this way- your cost per mile on E85 right now is probably about the same as running 93 octane. and even if it is a little more, it's worth it just for the way the car runs.