"and the MPG drops 6-7mpg" on E10.

Sorry but I do not see that kind of mileage drop or performance change.

 

I'm comparing my wife's driving with the A/C and heavy foot with no hypermiling techniques in a FWD FEH, not an AWD. I'm also comparing my hypermiling high MPG numbers with the '05 FWD on straight gas compared to the effects of E10 hypermiling. Other owners of the HCH and Prius are reporting the same drop in MPG hypermiling with E10 as I experience. The AWD is a totally different experience than the FWD FEH because of the drag. I think I would have a very high MPG like in the high 40's with your AWD on straight gas but I still think I would have a hard time getting high 30's on E10 in my conditions. Neutral coasting with P&G in a FWD is what really makes a difference in mileage over the AWD.

The Atkinson cycle engine is robbed with torque at low RPM already and E10 has a big effect requiring electric motor assist and runaway RPM on the '05 - '08 FEH. This is not near as bad on the '09 FEH FWD. Most V8 engines like in my '02 Explorer don't have this large drop in MPG on E10, but it has a drop I would avoid if I could get straight gas.

GaryG