Fitness App Inaccurate

Does anyone else see that the Fitness App does not keep up with your movement? As a software guy, based on what I see, it seems that the app just polls your location periodically and calculates distance, and change in altitude.

My evidence is that I can run or walk laps around a soccer field for 30 minutes without registering any steps. If I walk in a straight path, most of the steps are counted. I also climb and descend physical stairs, not a machine, and the app will count about 1 out of 3 ascensions.

I've been using the app for several weeks and my movement is invariably undercounted.