So, in order to just track mileage -- ie. to keep on top of maintenance schedules and just run an ongoing tally of mileage, I run Ride With GPS on my commutes.

Anyway, just looked at my 3day calendar and noticed some strange returns on the stats. The mileage seems right, as it's my daily door-to-door route. However, considering this is just a phone based app, no external sensors, how do the watts/calories/time combos imake sense? ie. what am I missing in how an app is measuring relative effort for a ride for exact same route? Of course I understand that that the eg. watts and calorie estimates are fictitious without any power meter, etc.. but I would have thought that the readings would be consistently inaccurate somehow.