It is rather odd; it'd be like San d'Oria only VERY rarely controlling Zulkheim. I wonder if SE, in designing the game, hoped that Buburimu would be just as much of a "place to level from 10-20" as Valkurm Dunes, given that subjob-quest items can be found in both of those places? Ah well.
Wish I could help, but I'm not Windurstian.