I use a Garmin watch. I am using my android phone to track steps for the game. There is always a fairly big discrepancy between my steps tracked with my Garmin and my phone. Today I walked just over 10k steps. My ateps in the game are just over 6k. This is a 4k difference. I am always having to walk sometimes 1k more to get the game steps to 10k.
I have no idea how to solve for this issue. The game is running in the background. Obviously, it must have not been to not track over 4 thousand steps 
Can you set up the game to use Garmin? Is this a possibility?