One of the most common reasons for steps to be different in Walkingspree and Fitbit to be different is the use of Mobile Tracking or Logged Exercise in the Fitbit Mobile app/Website. You'll see less steps in Walkingspree in these cases.
Mobile Run/Smart Track (Logged exercise)
Unfortunately Fitbit mobile run or Smart Track (logged exercise with GPS) steps do not transfer to Walkingspree. The Fitbit app uses the GPS distance data combined with your entered stride length to estimate steps and so it is considered non device data. We apologize for this inconvenience. Please do not use Mobile Run or Smart Track logged exercise and instead continue to use your device for your steps.
MobileTrack is Fitbit¹s name for the ability to use your phone¹s built-in activity tracker if it has that feature. More information on this feature is at http://help.fitbit.com/articles/en_US/Help_article/MobileTrack-for-iOS-FAQs So if you have a device and you left it at home, the accelerometer in mobile track could be used and it would update to your device. If you use both your device and app, the device over rides the app. These steps transfer to Walkingspree as they are considered validated steps.