QTR-Quadtone RIP

For UT2 ink and the 1280 printer how many shades of gray are there? 
Going from dark to light it's Black, Magenta and Light Magenta right?
 Cyan and Light Cyan are toners, I think, but they look kind of gray
to me.  I couldn't find the information at the MIS site.

Also Curve Creator/Ink Setup shows six colors for EEnhMatte-cool-1.
The last Light Magenta (LM) is grayed out but has a density showing of
17.2 with no limit.  Does this mean it's not used?

I'm ready to tackle my 1280 after making my first curve for my 2200
and UC Ink.  I'm very pleased with the results and would like to thank
folks here for the help.

Tom