Anyone from Missouri? MPG problems inside

[4MPG]

A few months ago I bought a 08 5spd hatchback (black) for my 90+ mile roundtrip to work. The car has about 6000 miles on it now. I was really hoping to see 40~ MPG on my daily commute, but I am getting far less than that on average. My commute is pretty straight forward, I have about 12 minutes of in city driving, and the rest is done on the highway (I-70 mostly). The in city driving has alot of hills, but I have figured out a way that lets me mostly avoid stoplights etc.

My problem is, driving 70 MPH on the highway (anything less is getting ran over on I-70) I can't seem to break about 36 MPG. Now that the stupid "winter gas" is in at all the local stations, I am getting on average 34.8 MPG on my daily commute.

On the highway, I just set the cruise and forget it, but in town I use DFCO as much as possible, or just pull the car out of gear and let it coast (idling) when it lets me get farther (aka no engine drag). I never press the gas pedal past about 1/2" (if that) regardless of being on the highway or in town. I am usually in 5th gear by no later than 35 MPH.

I have tried going 60 MPH (cruise on) on the highway three trips in a row and then filling up, and this did result in 39.8 MPG, but its almost suicide in this small car on I-70. People are blowing by you, flying up on your back bumper and then swerving over etc at the last minute, just a really great way to get killed.

My main question is, anyone else in Missouri experiencing this kind of MPG? I am doing everything I can think of to get more out of it but I am starting to think its the gas itself. We do have the stupid 10% ethanol in ALL gas (except some premium) so I know that's not helping, and I have heard lots of people say if they take a long trip they tend to get better MPG after filling up in other states. Could there be some real difference in our gas? We do have the cheapest gas in the nation, could this be why?

Edit: at 5000 miles I did the first oil change and swapped to full synthetic as well, but that did not help MPG significantly.