The 3ds Max FBX plug-in does not retain amount values for most Standard material map channels, such as Diffuse and Specular level when exporting. The FBX format saves only the bump map channel amount and sets all other channels to a value of 100 on import.
The 3ds Max FBX plug-in reads the glossiness and specularity amounts from Shader Basic Parameters and not from the Maps rollout in the Material Editor.