The contents of a routine AIREP include turbulence of any category. A special AIREP is required when encountering severe turbulence (and a list of other phenomenon which affect the safety of aircraft). I can find a question in our databases in met which says 'all pilots encountering turbulence are requested to report it' and then leads on to test a definition of moderate turbulence, but I can't find either a question in met testing the requirement for 'severe' as against 'moderate' in a special AIREP or the equivalent question you quote in Comms. May I ask where the questions came from?