Hi MDO2010 I have no idea why this works as it does but only works in eevee. In the principled shader and tying to set up something similar using nodes in cycles and the glossy has no effect at all on the output. With eevee though the glossy does effect the amount of light reflected off of it with the metallic set to 1. My main point with it is why is a single input into a mix shader adjusting the strength of that input. When to me it is designed to mix 2 inputs together to give a combined output.

Incantrix