Why is the calories remaining different on My Fitness Pal vs. Fitbit?

[familyfive]

Why are the "calories remaining" different on my fitbit vs. My Fitness Pal?  They are linked together with the same goals set for both programs.  I'm not sure which program is correct??  My Fitness Pal is giving me credit for a fitbit calorie adjustment but fitbit does not give the same credit so results are not consistent.

[Collin1000]

#1) Do you have the same deficiet configured in both? That is to say, if your fitbit food plan is configured to be -500 calories, is MFP configured the same?

#2) Are your body stats the same in both? height,weight,etc? This can throw off calorie calculations.

#3) Is your fitbit food plan set to personalized or sedentary? MFP uses the "sedentary" model, so you will need to switch fitbit to use the same model at  http://www.fitbit.com/foods/log