The owners manual is emphatic that the UMC should sit flush against the outlet box and includes pictures of correct and incorrect situations. I note however in my case that the weight of the UMC causes a slight (1 mm.) gap between the top of the plug and the outlet face. I therefore improvised a solution for both the 110 and 240 (14-50) plugs using bungee cords. Your situation may be better than mine but if not, you may want to consider this.
