textures are automatically filtered for LoD, it is called dxt mip levels. when you pass a texture into CMP they are converted to .texture format, which contains the mip levels. the level displayed is selected dynamically by the game. this is why when moving from one place to another over a long distance the textures might appear blurry for a second.
if i had another texture for each mesh LoD it would just be taking more video memory for no reason because each one of those would get it's own set of mip maps. this would also cause each model to have to load many more textures than it really needs.