Color-dependent plot-style tables (*.ctb) refer only to the index colors,
you want to change objects with TrueColor colors in the plot output,
one must resort to a completely different concept.

Named Plot Style / Plot Style Tables (*.stb) - There is a lot to learn.
The plot styles are COMPLETELY INDEPENDENT of Layer and object colors!

4U => http://help.autodesk.com/view/ACDMAC/2017/ENU/?query=stb