I know what you're saying - yes, there does seem a big difference. Now, here's the thing. In fact I've kept the 3 shaders (so including the blender) connected to the GC AND I've then connected the math function with the smoothstep into the diff reflectivity control - even darker eh. But I'm still getting results I feel are perfectly acceptible (to my eye at least). It's giving me the softness in the terminator that looks correct to my eye in the lower lighting conditions while still holding up with brighter setups. There may be some difference with how we're using lights here.
I think you just need to play and find what works best for you in whatever lighting conditions you're working with.

 

PoserPro2014(Sr4), Win7 x64, display units set to inches.

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