The maps are generated automatically within the NWN engine as the areas are made and laid out, they are not made separately by hand. So if something isn't reflected on the map, there's absolutely nothing anyone can do about it to change that, since maps are generated automatically from the area that was built. It might not show because it is a prefigured terrain from one of the haks, or because there's not a lot of ways to show multiple levels on a flap map without a ramp added to show there's a way up it. Hope that helps.