Why do I get more model data files delivered if I select a part of a province or a water board?

ArcGIS files of DGM and REGIS II can only be delivered as zip file of a entire province or water board. You receive the provinces or water boards that are part of area you selected. ArcGIS file of GeoTOP and DGMdeep always contain the full coverage area, independent of the selection made. For SubsurfaceViewer files also the entire coverage area of DGMdeep is deliverd, but for the other models (DGM, REGIS II and GeoTOP) only the tiles included in the selection are included.