The reflectivity can be tuned to anything you like. If the model already has a _s.dds file then it's just a matter of adjusting the brightness levels of the areas of the texture you want shiney or flat. If the model does not have the reflectance texture reference built in you can use the _t.+sr.dds extension to add it after the fact, but his requires a minor hex edit of the m3d to be fully functional.
A brightness of 16% grey is quite reflective, and 4% grey is like flat matte paint. Above 16% is starts to look like chrome and eventually becomes a perfect mirror finish. Many of the existing _s.dds files are too bright to look natural with AnKor's Shaders.
Additionally, they often include false shading that is lighter on the upper surfaces and darker on the undersides. Unfortunately this only looks correct when the aircraft is flying straight and level or sitting on the runway. Anything else and the shaders are fighting to light the model correctly while being fed this incorrect information about the model's orientation relative to the light.