The other thing is you want a secondary reflected color down below some of your shadows (which are really reflected shadows). Most NMM looks like shit including supposedly good stuff because it looks like some sort of pastel sugar cake decoration with no real shine or hardness to it. Which happens because people don't push the value enough on both ends.
The best thing about forced highlights and shadows is that they work at least as well with actual metallics because the principle is unchanged. My personal favorite is metallic highlights and midtones and matte, more colored shadows. It is both the most painterly and interesting and also the most realistic at the same time.