Despite Stream Sync, my streams are innacurate

Spotify has a new “Listening stats” feature, or at least i just discovered it, and it shows different data compared to stats.fm. (for instance, I listened to a song 9 times in a WEEK, yet stats shows i only listened to it 5 times the entire months. This makes me question the integrity of my data on stats. I occasionally do reupload my streaming history, but if i have to do it every month, then whats the point of having this app to track it?