Re: thoughts on MPG
A light breeze? Didn't think it would skew it that far though... is your route an uneven split between uphill or down? 60/40? Does the traffic go in one direction more than the other, adding to the breeze factor? Did you let the motor cool off completely before the ride back?
These all seem like small factors by themselves but, add them up and consider how little power is actually involved in these engines.
Try the trip a few more times, maybe ten... average out the numbers from that. They will still be biased to one direction but we may be able to close the gap a lil bit.
Or just average these two results which is around 85 or so!