If you keep an eye on the user manual of IMC - page 22 - there is a description, which colors are supported by Navicos NOS platform (HDS e.g.) and which colors are supported by both, the NOS and INDIGO platform.
"The following color table is split into a common color scheme that is supported on both the NOS OS
and Indigo OS and an extended NOS color scheme that is only supported on the NOS OS. Using a NOS
OS only color on an Indigo OS unit can create unexpected effects. For that reason, the color choices
in the shapefile will have an effect on the generally regarded support of the AT5 itself."
(User manual 0.6.5.1 Insight Map Creator
http://in-touch-with-adventure.de/downloads/InsightMapCreator_0650.pdf)