Maybe so, I just clicked on the "help" button in the dialog and it says this:   Click in the Extension column to type how far the selected layer extends past its default bottom elevation, either at the bottom of the wall's bottom plate or that of the floor platform it builds on. Only available for Exterior wall layers, the highest Extension value is also applied to the wall type's Brick Ledge Depth, set on the Wall Properties Tab.   My guess is that the tech article you fo