The Reflective Coat material layer is created with the Add Layer option and cannot be found in the Creation menu of V-Ray Asset Editor. It has the same parameters as the Generic Reflection and it provides additional Opacity and Multipliers modifiers.

Opacity

Opacity – Specifies how opaque or transparent the material is. A texture map can be assigned to this channel. 

Mode – Controls how opacity is sampled.

Clip – (Very fast) The surface is shaded as either fully opaque or fully transparent depending on the value of the opacity map (i.e. without any randomness). This mode also disables the filtering of the opacity texture. This is the fastest mode but it may increase flickering when rendering animations.
Stochastic – (Optimal) The surface is randomly shaded as either fully opaque or fully transparent so that on average it appears to be with the correct transparency. This mode reduces lightning calculations but might introduce some noise in areas where the opacity map has gray-scale values. The opacity texture is still filtered as normal.

Multipliers

Mode – Specifies how textures and colors will be blended by the multipliers.

Multiply – The texture is blended with a black color.
Blend Amount – The user-specified color is used for blending

Reflection Color – Controls the intensity of the reflection color.

Reflection Glossiness – Controls the intensity of the reflection sharpness.

Opacity – Controls the intensity of the overall material Opacity.