Geographically Belgium is challenged as it's sorrounded by many major airports. Paris, Frankfurt, Amsterdam, London area, Dusseldorf, Cologne etc. This gives us a lot of vertical movements in a limited airspace (Belgium is tiny). I don't know that our declared capacity is too high, but we are nearing the limit. And because of all the vertical movements it's difficult to just add extra sectors.
Perhaps your LOA needs renegotiating?