My MPG is better than your MPG...

[Sean]

Originally Posted by Homeslice

You are comparing two different time periods, one with Oil A and another with Oil B. Your truck isn't operating in a controlled test, so there's too many uncontrolled variables (weather, tire pressure, trip distance, etc) for you to declare that your 1 mpg improvement was due to a different brand of oil.

Lacking a time machine, I averaged things over several thousand miles.