Not at all. It's just that, for example, the CAA won't accept a pass in the German PPL exams to be used for the issue of a British PPL - even though both are JAA states.
I think that there is reciprocity between the IAA and CAA, but that's about all.
As an example of how some JAA states conduct their PPL exams, a certain nation's JAR-FCL PPL students somehow manage to pass the whole Navigation and Radio Aids examination in 20 minutes. It has been alleged that the exam answers are available 'for the right price'....