I figured it out. When the criteria is Visibility is visible, then Vectorworks counts the objects that are visible as defined in the navigation palette, and that includes the visibility of layers. My problem was I placed the worksheet on another design layer, Design Layer-2, and expected it to count the visible objects on the Design Layer-1, but I had the Layer Options set to Active Only, so even though the Navigation Palette has some classes set to visible, when the layer is not visible, then Vectorworks can't count the visible class objects in that layer. Now that I understand this it does make sense. Also, I find it best to place the worksheet on a sheet layer in this case and use Multiple View Panes, then I see the worksheet face on in one pane and the layer and visible objects in the other pane. The worksheet counting is correct that way.