Please educate me on where I could have picked up error in my measurements
Comparing your Jeep to mine, Squilt, I'll believe your numbers.
Yours, with skinny 30" tires, probably at stock height, with 3.73 gears, and probably has the OEM speedo gear, probably reasonably accurate. Taking it easy, drafting semis, on fairly flat highways, 22 MPG sounds reasonable to me, especially compared to mine.
I can get 18 MPG on hilly terrain, limiting to 60 MPH, no semi drafting, on 33" tires (taller and wider), with the brick of a body up in the air at 2" lift plus 1.25" body lift, LJ (heavier), hardtop (heavier), 4.56 gears, GPS-calibrated speedo, at 5K to 6K elevation (15% - 18% reduction in power).
