I also use Samsung Health app on my phone. It tracked 13000 steps taken today. But Wokamon only tracked 2000 steps! 
@wokajenn Can you please try to open Wokamon before the day starts? Different Android app has very different pedometer implementations. The Samsung Health app is able to track your steps because it is a system app and will always open when you start your phone whilst other 3rd party apps have to be opened manually by users.
Hi @marspark
As can be seen from the first screenshot I uploaded above, I did open my Wokamon app before the day starts and hence why it is able to track my steps from 6.20am to 6.48am. The second screenshot above also shows that my Samsung Health app also started tracking my steps at around 6.20am.
However, the Wokamon app stopped tracking completely after 6.48am for reasons unknown and I did not realise that until I open the Wokamon app again at the end of my day at around 10pm. That is when it starts tracking my steps again.
Not sure if it is a bug in the app or a problem with my phone. :S This is the first time it happened - did not encounter this problem before.
@wokajenn Any 3rd party app can be shut down without notice if the operation system needs to acquire more memory. Some phones have a ‘whitelist’ to prevent the system from killing certain apps. If you can let us know your model and operation system version then maybe we can google it for you.