I wish I had taken my own advice now.
I had to manually adjust my fillup value and it's at 15% now but I still think the numbers are a little too "generous" for what I'm doing. I won't know for sure until I go back to the pump but that won't be for another 2 weeks (ideally). Again, I'm not sure if it was the gas or the tune-up or the tires... too many variables to deal with.