Delphine and Arik,
I passed my exam in Dubai where only "natives" are allowed to proceed for a 10 minutes interview in order to validate a level 6 (of course natives means English native speakers, not Arabs from the UAE...logic isn't it ?). As a non "native" speaker it is obviously not possible to obtain a level 6 out of Dubai (the exam was outsourced by Jeppesen on behalf of Emirates Aviation College, so I guess it's same wherever you proceed with Jeppesen...)
I also heard from a British citizen colleague who lives in France that he couldn't get a level 6 since his examiner was not level 6 and that he should go to Paris for that and.
Beside the fact that I don't really care about a level 5 or 6, this situation is (as usual) totally silly and inappropriate to assess pilots' communication skills while it's not encouraging "natives" with strong accents to make any improvement effort in order to be understood. On the contrary, they are reinforced with the feeling that they are the reference... pathetic.