Indeed. When you were young (and I was younger) no one had fancy computers to keep track of moving time vs. stopped time. You just looked at your watch. And according to the physics books, average speed is total distance divided by total time. That definition makes sense because time spent resting, eating, waiting for traffic etc. is an essential part of the ride. As an indicator of your accomplishment total time of 8 hrs is better than 8 1/2 hrs even if that extra half hour is just resting/eating.

Of course nowadays people quote the moving average figure because they can and it is more impressive. Even so, your 8:27 ET is dadgummed good!