YouTube Question Youtube watch hours keeps dropping...WHY?

[Paddle & hike]

Everytime I get closer to 4000... Youtube take away a couple HUNDREDS hrs! that's insane! WHY???

So frustrating to work so hard for these hours... (yes, i'm set with "365 days" in settings).
But I feel like they just want to keep me under the 4000 line forever.

Any ideas or tips?

Thanks