Converting from Iray to 3DL -- newly applied 3DL shaders not behaving

I'm trying to convert textures on Sixus' Mechanya geografts from Iray to 3DL. After zeroing out the shaders and materials on Mechanya, any 3DL shaders that I apply come out weird. This does not happen to other Iray-only things I have converted.

As an example, here's a crappy render. The Mechanya neck piece on the top has had all Iray materials and shaders zeroed, then Marianne's Shiny Plastic Shaders [3DL] applied. It should be black shiny plastic, but it's looking grey instead.

The bra piece on the bottom has had all Iray materials and shaders zeroed, then Marianne's Shiny Plastic Shaders [3DL] applied. It's actually lokoing like black shiny plastic, as it should.

Any suggestions for the problem with the Mechanya materials? It looks like the ambient is cranked up too high, but fiddling with that does not appear to have any effect in the render. Thanks in advance.

--MW