I don't have the answer but I find it interesting the buttons are in different places if you simply rotate the unit. From a manufacturing standpoint, it would seem easier to simply use the same hardware and layout, and just use different faceplates/buttons for the different orientations. That would make manufacturing simper and easier, and it would make it easier to rotate an installed unit. I imagine they did it the way they did for functionality reasons, i.e, the placement of the controls fits an ergonomic model of some sort.