My SG recalibration was so far off, I felt I had to fill up to get some sense of normalcy back in my monitoring system.
Check out my first post-wheel-mod gas receipt:
And here I thought I had a crappy day! Since the SG was so far off -- about 8mpg too low -- I couldn't hit any of my marks, and gave way more gas than I should have, just to keep my speed up. It was terribly confusing. About halfway through the return trip, I figured out that I need to aim about 5-6mpg lower than usual, based on my previous marks, and just as I got it into my head that I was going to beat 30, I ran into an uphill pile-up! I was totally baffled when the gas pump shut off when it did, and it took me quite a few startled seconds to recognize the easy "divide by 2.0 gal" calculation.
So can we say, "Way to go, wheel mods!!" 
Of course, such a short tank is bound to have a large error. So we'll see how the rest of the week goes. Maybe I can get another mod in tonight.
