I've not manually reset Trip A since I bought the vehicle. The miles rolled over to 0 at 10K, but the calculated average didn't change.
Mine changed calculations to be based on 0 point mileage.
Ugh, let me try to say that differently, which may or may not help.
Let's say I was at 25 mpg at 9,999 miles. First off, those of you who know how I drive know that's not possible. But, let's skip that.
When I rolled over to zero miles, I still had 25 mpg, but the thing acted like it does at zero miles, so, if I suddenly hit a stoplight at 0.1 miles, my 25 mpg dropped rapidly, instead of doing not much of anything (as one would expect with 10,000.1 miles). It calculated off 0.1 miles.
So, short version is, I suspect it uses the miles displayed in calculations, even though it maintains the mileage.
I'll test again soon. Or so I'd suspect.
