FWIW: when I get or start using any "tracking" app regarding caloric burn, I wear my chest strap (nothing is more accurate!) heart rate monitor and MANUALLY OVERRIDE the calories burnt for several days. I do this for my usual activities: walking 2.5mph, walking 3mph, walking 3.5mph, walk-run, 5k training, hatha yoga, circuit training.
It's sort of a drag to bother with this but I'm a data freak. I want my data to be as real / true as possible!
If you don't have a HRM, it's a great training tool (when you learn more about HR zones!) for whatever you do -- not just "am I working hard enough" but "am I working TOO hard" or "have I recovered enough for the next set?"
As I said, I'm a freak for transparency!
I do NOT like Fitbit's logs/ tracking (sorry) but I love the DEVICE. So, I track everything on MFP and I'll use my HRM and Nike+, etc. for input data (I only do that the first say 5 or 10 times that I do an activity--after that, MFP "knows" a good guess at what I've burnt if I do circuit training for 20 minutes rather than the usual 25). Hope that makes *some* sense!