Phong multi point

is there anybody out there who used joreg´s PhongMultiPoint (on his userpage) and had similar difficulties like me?
To get a proper shading on imported meshes I need to lower the light parameters “power” and “falloff” to 0.0001 and put ambient and specular colors to almost black - way darker than what appears in the renderer…

Also it seems that the mesh still brightens further up when seen from a greater distance with lookat - or when ortho is involved with a higher far plane.

Advice or hacks?

Multiple Point Lights.rar (3.6 kB)