Color Management why CMYK and RGB are different

RGB is transmitted,  it projects, the white is the maximum presence of all color. Black is the absence of all color. The white and black points of a display are determined by the hardware quality and the software configuration.  A reasonable quality display can display an RGB gamut of Adobe RGB or slightly larger.

There are many RGB color spaces but all are constrained by 256 shades of each base color. Therefore proper display or conversion requires each files to be labeled as to its proper RGB color space. As there are always conversions of RGB when printed this labeling is mandatory. 

CMYK is a reflective color, the white is the absence of all color and black is the presence of all color. The white and black points of a media (paper or other substrate) are determined by the whiteness of the media and the ability to absorb total ink determines the black point, called the TIC (total ink coverage).

There are many CMYK color spaces but all are constrained by 100 shades of each base color. Unlike RGB the CMYK files do not require conversion upon importation into Draw, the CMYK numbers will be processed as imported.

The reason CMYK does not require conversion upon importation is that during printing the imported CMYK numbers with be processed and converted by the output device against its ink limit (TIC),  lineirization dot gain curve.

The only requirement for the best CMYK output is to know the TIC of the destination device. If the service provider gives you a CMYK color space recommendation you can determine the TIC by loading their recommended CMYK profile,  then create an R0, G0, B0 object and convert it to their CMYK profile,  read the converted color with the eyedropper,  adding up the readings of each channel with give you their recommended TIC. 

You may then use any CMYK profile of equal of slightly less TIC.