One that you opened the document you will see the preset of colors that you want to use as color mode. One when you activated, you will have the document with this color modes.
The Corel say the first option wich is automatically only in RGB mode, that is how Corel see that mode if we want to print from Corel for web. This option must be set as program changing. Which is the question which color mode will be a primary for use. You have CMYK and RGB.
The second option is color modes which we want to use for work. If we want to use for print, we will set that on CMYK color mode-very simply as a Photoshop Color Mode.
I think that the problem is on Spot Color definition, because, you want to work only in Grayscale mode to print black and white, I think that here is the problem.