Name and Description are attributes inherited from ifcRoot. So it is rather a question of how attributes are derived when AC creates ifc entities from native entities and it would be nice if we had some more control over this.
For stories Name is locked to the name of the viewport and Description is not derived.
This doesn't really answer the real question - why can we use property mapping to override some attributes of some entities but not all?
And I guess that it in the case of stories it comes down to that AC doesn't have a clear-cut entity corresponding to ifcBuildingStory and even if it did the relationship between many parameters would be 1-1 so mapping doesn't really make sense. However, we should be able to control that ifcName is derived from story number instead of name and that ifcLongName is derived from story name. We should also be able to add a note to each story from which ifcDescription is derived.
True about IfcLongName. Being able to override the mapping is what I need anyways. We're working with Archicad, Revit and Tekla to begin with with the purpose of crating IFC-export templates so that the IFC-model has the same structure and content regardless of cad program or localization. It's a very basic requirement but desperately needed. We showel all needen properties into one dedicated pset and that's all fine but all ifc-programs have this cunning Summary folder with hardcoded content and it's here I can't get the name of the storey to show.
I guess that it is the IFC reader that decides what to show in ID/summary tabs but since Name and Description are root attributes they are safe bets. Solibri doesn't seem to show LongName by default, BIMcollab does.