Greetings;
In the time before you stopped, you were getting instantaneous mpg readings higher than the averages in both trip memories. Both are increasing there averages (this is when having 100ths would be revealing) but at a different rate due to the mileage they're tracking as well.
You just observed the .1 level event, while the .01 events would have been "normal". I noticed this behavior as well and agree that it does raise an eyebrow. Just wait till your instantaneous mpg is between the two trips, they'll move in opposite directions if watched long enough.
Just my 2.00 cents
