Interestingly, the WSET Level 3 is called "Advanced" just like the CMS Level 3 although the latter is obviously considerably harder. This also fits my earlier five level system of: beginner, intermediate, advanced, expert, master.
There is a WSET Level 4 which is considered a Diploma.
Although not a WSET qualification, the Master of Wine requires a WSET Level 4. In this sense, a Master of Wine is basically a kind of Level 5 so it really does fit the "beginner, intermediate, advanced, expert, master" model.