Chinchilla.612. you're not quite right there.
Just for your info, all of the light jets below 5,700kgs are certified under FAR/JAR23 (The CJ series has continued to do so as they have upgraded the models)
However all performance is certified to FAR/JAR25 Commercial standards.
If you look at all of the performance figures for all CJ models EXCEPT the classic CJ (which has a gravel supplement) it within the simplified section it specifies PAVED RUNWAY to use simplified figures. Under FAR/JAR25 the aircraft is to use paved surfaces unless a supplement is published. The rest of the CJ series has no supplement, therefore grass/gravel is not an option.
Citations have a habit of nose-ing in on grass, if they don't have a nosewheel spin-up modification required for operations off paved surfaces.
Hope this is of a little help.
SKP