The more i look the more it seems like there is some confusion as the chinagraph brand as well as those staedtlers seem to be a leaded colored pencil with some type of permanent hard wax added, and lots of people seems to use that type. The confusion looks like it comes from people using the name chinagraph in error and intechangeably with china marker which is a grease pencil and a completely different animal.
We don't use wax loaded pencils in airbrushing because no water based paint would adhere to it, you're maybe looking at another type of pencil from the same brand, most brands will produce several different types of pencil.
Why not post some links to the stuff you're looking so we can see where you're having a problem?