FitBit exercise/activity calories include BMR but BMR portion not deducted in Cronometer
I understand FitBit calorie calculations for an exercise actually include BMR. It would seem to me that because Cronometer already accounts for BMR calories the BMR portion of the exercise entry would therefore need to be deducted from the calories synced in Cronometer. For example: my BMR = 66kcal/hr. If I do an exercise activity for one hour and FitBit estimates say 500kcal that would be 444kcal for the actual exercise itself and 66kcal being due to my BMR. So, I would expect 444kcal to be the number that should be input to Cronometer. But this is not what happens, instead the full 500kcal is recorded thus it seems to me it's doubling up on the BMR calories for that one hour exercise period.
Is my thinking correct on this or is there something I'm not understanding?