It remains normal at all speeds till you stop, but the average dropped to 12.7 to 12.2 when I was stuck in traffic. If you drive this thing at speeds the average improves, I mean a constant or steady drive in 60 to 100 kms/hr zone keeps the average good. Stop and go and bumper to bumper traffic and slow speed decrease the average, but not that much.
Another factor might be that my MID was showing average of 11 kms for the past one month. Today I reset the average and it started showing improved reading. 