Lefthandseat - yes the FAA do write the syllabus, however here is the thing..........you also need to pass the Sheffield course, which is about 10-12 exams on top of the ADX and oral FAA part.
Most students are able to complete the ADX part in week 2; 95% of the hard work is passing the Sheffield exams (as well as coping with the daily oral test sessions!

).
The Sheffield syllabus is way more than the FAA requires and thats why Ops managers like people who went there.