I have not clue man,I looked up the refraction index for skin and thats what i got...Thats why i said "whatever for that" I do not think anything has a negative refraction index either.but positive values screw up the bump big time...looks like she is covered in sand,like you see on the left edge of her face.as for the SSS being gone..the more i look at it i have to agree you are right.The first image did have that "healthy glow" that skin does.but the second one i think has a more natural fleshy color.

"Many are willing to suffer for their art. Few are willing to learn to draw."