It's been many years since I ran into this problem … so I've completely forgotten the answer :-}
New set of corporate colours, with definitions* including CMYK. I check them by filling a rectangle in PhotoShop – perfect match with the sample document. I define a new colour in FrameMaker (FM12, if that makes a difference) using the same CMYK values and get a visibly different colour.
What's the trick for getting the same results from the same values in both environments? (and PhotoShop has to be the reference)
* full set: CMYK, RGB, hex, Pantone (number not recognised by FM12), RAL