Change level LOD distance without regen

Hello! If someone could help me with this task i’ll be very grateful, so - How to change level LOD distance without regenerating it (afte it’s generated), or maybe how to disable proxy mesh generation for meshes that are placed in lod0 level (aside from landscape, this proxy generation process for meshes - takes forever).
For example - standard proxy mesh generation for a set of meshes takes 2 min, and for the same meshes when creating level lod it takes 15 min.