How to set right LOD in fooliage grass type

Hello everyone!
I’m trying apply grass type fooliage with rock for my material to create rock with low poly rocks on it.
For this I use grass type with my setted rock and set for it Min LOD 3. In rock asset I set LOD 3 and reduced the number of triangles. And save it all.
But in asset’s viewer I see low poly rock and on landscape in result not low poly.
What I doing wrong?