in this instance it was very easy to spot, tho I have to admit that I feared that there might be some kind of cutoff built in so I never used it more than twice
as the manual is now not particularly up to date I dont see it as a problem that there are features that are not in it. In this instance it simply needed looking at the production page and seeing how you could cancel each section of an order to work out how to use it, so it looked more like a feature than a bug to me.