I am having the same problem using a Polar Loop with my iPhone 5S.
The prioritising function doesn't work as the iPhone continuously adds steps for a certain period of time (a couple of minutes) whereas the Polar Flow app, which communicates with the Polar Loop activity tracker only syncs only when you command it to.
I think this shouldn't be a problem if the Polar Flow app also gives a time period to the synced data, because then the Health app will probably recognise that for a certain period of time there are multiple data sources and it will prioritise using the priority list.
However, the Polar Flow app doesn't define a time period for the synced steps (it does, but just 1 second at the time of the sync).
I think this is the main problem with tracking with both iPhone and a Polar Loop, resulting in double counted steps. Which is, I think, a problem with the Polar Flow app.
The double counting can be solved by:
- Changing the Motion & Fitness Privacy settings (in iPhone settings) so the internal iPhone motion sensor may not write data to the Health app. Disadvantage is that this also prevents other data apart from steps to not be synced, like walking and running distance and stairs climbed etc.
- Delete the step data provided by iPhone manually in the Health app, as suggested by Barry. This is tedious.
In my opinion, these workarounds are not satisfying. Ultimately you do want the iPhone to count steps in case you forget or choose not to wear you activity tracker.
I will try to contact the Polar Flow team, to hear what they say about the problem.
