Like I said there is no O/D switch on a 2011 Edge, that is a grade assist button and your picture clearly states that. What that does is cancel Overdrive and puts the transmission into a different mode that alows it to brake when the vehicle meets certain conditions. Please read the picture that you attached so you can understand it is not a O/D button and so you can actually find out what the transmission does when you activate the grade assist feature.
I cant find anywhere in the Manual where it says there is an O/D button on a 2011 Edge.
Now on older vehicles there is a O/D switch and it does turn off O/D and that is all it does, on a 2011 Edge that switch does much more that the old school term you are using.