oh well ... today was back to work and my MPG went down as I expected. I also realized that a section of highway I HAVE to use every day has a lot more resistance than usual. When on this stretch of highway my instant MPG goes down a few points and goes back up when I get out!
So now my average FE on this tank is 5.7l/100km or 41 MPG.
I already bought a flip switch and I'm looking at the diagrams to install it and start to EOC a bit!