Physics material density and object mass (weight) + scale issues

I tried to set up physics material with custom density.
It works great, but for some reason, it now allows density lower than 0.09
It allows to put it there, but box 1x1x1 didn’t not go under 90kg
I was able to create less dense material only by using “Raise mass to power”
But then another shock. When I scale the object down it scales down also mass, but When I scale it up over 1 it remains the same as on 1.

But also scale down is not correct, when I scale only the z axes to 0.5, it is 2x smaller. The original box has a weight of 100kg (with a density 1g/cm2) and the scaled has 12kg. Half of 100kg is 12kg? And when I scale all axes zo 0.5, it should be 1/8, but it is still 12kg. Do you know why, please?

Why everything simple is so complicated in UE?

I found an issue with the wrong mass (weight) when scaling was fixed in 5.1.
The remaining issue is the impossibility to enter a density smaller than 0.09