Daily Steps, FitBit

Hi.
I've recently bought a fitbit one monitor and like it a lot but wondered how other people used it.

I am quite sedentary thoughout the day but aim to clock at least 10,000 steps a day - I average 12,000 in fact.

Often ( nearly every day ) the majority of these are earned on the treadmill for 45-60 mins.

MFP awards me in the region of 600-700 calories extra earned from exercise a day, which I tend not to eat back - usually I'll eat around 1300-1400 calories in ratios of 45/25/30 carbs/fat/protein.

I'm not losing a lot and though I am not looking to shed much I'd like to know what others

a) think of this approach
b) your experiences of fitbit with mfp and
c) if you think the accuracy of the two together is reliable - eg the extra cals earned from exercise

Thanks!