Generally, if you plugged in the correct tire size, your bike odometer should be more accurate than any car. It is pretty easy to get new tires for a car that differ from the originals by 10% in circumference. Even tread wear can make a 3% difference. That would equal 6.1 miles +/- 0.18 miles for the car just on tread wear. Regarding the geometry of your ride. Swerving around catch basins etc. adds negligible (less than 1%) difference to the ride. Even crossing streets etc. does not add to much. Most of the difference will be in the circumference of the tires. That said, why the interest in 3 decimal points of accuracy. Just tell folks you commute a little over 6 miles. By the way, based on your numbers your top speed may have been only 24-3/4 mph....or, it could have been as high as 25-1/4. You can check your bike odometer setting by marking the wheel and rolling the bike forward. Check it against several revolutions on a smooth surface.