The demo scene that comes with the Simple LOD package has 3 copies of the same scene contents. The first has all the original gameobjects as they were downloaded from Unity. The second has the same objects, but now the meshes are merged. And the third uses generated LOD levels.
The demo scene can be played here
You can switch between the 3 identical scenes with the buttons on the left.
When you click an object it is selected and the details are shown in the top left corner.
Manoeuvre with WASD and the mouse.
Click drag will turn the camera
Demo scene: original models
We start with 198 materials and 368,933 triangles
Demo scene: merged models
When the meshes are merged per object we get 59 materials and still 368,933 triangles
Demo scene: LOD levels generated
When we generate LOD levels for all the objects we end up with 59 materials and 171,108 triangles. You can see which LOD level is used per object.
Demo scene: LOD levels viewed at some distance
When we zoom out the number of triangles is further reduced to 57,791.