You mean you put the OEM wheel covers on? I still have mine, maybe I'll put mine back on. I just made an approximately 1,000 mile run down to near Baton Rouge, LA and back (south side of Atlanta). I tried my best by GPS numbers to put the car on 73.5 mph. I did so because the mpg graphs in the forum suggest that ~73.6 (or so) mph should yield 40 mpg. And I wanted to get at least 40 mpg. I think I got it reasonably close to 73.5. Of course the speed varied ± 1.5 mph but hovered around 73.5 mph very decently. Very little A/C useage, maybe 15%. Just me and a throw bag in the car. After all the math, I got almost 41 mpg. Not nearly as good as yours. I think I was running only 40 psi, and aftermarket wheel covers.
My wheel covers are crap quality. They look(ed) nice, but I lose a couple percent of them every time I go through the car wash!
Perhaps I'll stick the OEMs back on some time.
You going 3.5 mph slower, and having a sedan, your car SHOULD do better mpg than mine (and did). I'm a little jelly. However, I wanted to try a hatch, and I'm not complaining. I do like my hatch. However, I haven't had an instance yet where a sedan wouldn't have done something that my hatch did.