It dropped to 30 deg here and I checked the tires as my wife was down to 32 mpg. I found that the tires had dropped from 34 psi to 30 psi so I put 40 psi in and she is now getting 37 mpg.You get a planet every 200 Eco points. No significance on the type or order.
Look for several threads here on winter gas millage. In short, it will go down. Main reasons; Engine runs more to warm up the car, winter blend gas, and gas less efficient when cold.
The TPMS only comes on below 30 psi. Many members put max sidewall 44 psi to get the most mpg but it gets pretty bumpy.Do the tire pressure monitors have a problem with higher than speced pressures? I ran mine to 36 when the sensors came on this AM and didn't want to chance it until I checked here first.