I having troubles understanding some things wih my fitbit flex. I have it paired wit my fitness pal. Today I logged 35 minutes of being active in my fitbit app. When I synced again it showed I only had 9 minutes? ?? Why would it change....also with my fitness pal I had a positive with my fitbit calorie adjustment and logged back on to input a snack and those calories have now gone to a negative? Any idea hy?