My impala would pull down 32 on straight highway drives before the ethanol mix, last trip to Ga it pulled down 27. My camaro which had the same engine as my impala and weighed less than 200lbs difference would pull down 24 around town. The impala is getting 19. Sounds like a pattern forming to me

Edit:
My bike doesn't seem affected by it though, I wonder if it's the smaller displacement, higher rshared_pm range, wasted spark ignition, or some combination of those