Java_avaJ Don’t worry about the number, it is perfectly normal for it to be higher than “normal”, especially at first.
At the beginning there are more fines, so you have to grind coarser to compensate. As the burrs bed in, the level of fines decreases and so you make the general grind finer to get the same resistance. I suspect the higher level of fines at first is why the impact of a small change is so dramatic.
When I first got my niche I was in the low twenties. Over time this reduced to the low teens. Now that I can play around with pre-infusion and use a vst basket I tend to be in the 6-10 range. It does depend on bean, dose and basket though.
The numbers are really useful for allowing you to quickly and easily change bean or brew method. I would completely ignore them for comparing against other peoples setups.