The expansion kit had two major problems; first the holes in kit side pieces that support bracket that hold them together were not tapped to accepted the supplied screws, making it impossible to assemble.  Second, when I did drill out, tap and assemble support bracket, the bracket, which runs horizontally across top of unit, was directly over the mounting holes to secure microwave to cabinet above microwave.  This made the support bracket useless, so I used duct tape to hold the side pieces together.