Stop in for a cup of coffee

Riddle me this.

On the drive thru PA, I averaged 19.2 mpg there, 19.4 mpg back,

But in Ohio and Indiana, I got 15.5 there, 17.0 back?

Running 80 the entire way? Except for the part on the way back on route 30 in PA
PA moved all their mile markers closer together. Then they can claim they have more maintenance. Why do you think our gas tax is so high LOL