Well, I did the 210 mile trek again yesterday, & my average is up to 25mpg now. I'm not doing any stop & go until the very last 2 miles off the interstate. I used the cruise as much as possible, but I didn't notice the weirdness of speeding up. It was very smooth.
One thing I did notice that I thought was weird on the mpg EVIC is that the display is not proportional; i.e. going uphill displays 10mpg, but going downhill displays 80mpg! That was just weird.
If I am understanding your statement correctly, the EVIC should show lower mpg going uphill than when going downhill. If fact with most fuel injected engines, the fuel is cut off when coasting downhill.