Wing Root:
This config is a legal or operational requirement by some authorities and/or operators, depending on how they handle the typerating/prof-check issue when their pilots fly both -3,4,500 and NGs.
At our airline we are using the "modern" type display (therefore the older one is not certified) on the NGs; simultaneously we're flying -300/-400s on one typerating. The only condition being an alternating profcheck.