I don't think it's as obvious as you say. If the edges of two objects are at exactly the same position, do they overlap? It depends on where you say the object ends - does it end just before its edges, or does it include its edges? Unfortunately we can't change it, mainly because the Platform behavior heavily depends on this.
I understand that for reasons you know better than anyone it can't be changed but I'm just adding my point of view, if an object with the size 20x20 is located in the coordinate 0,0 and another object with the same size 20x20 located in coordinate 20,0 then they are side by side, they are touching each other, it's like touching a finger with another one, they do not overlap, but if the second object is located in coordinate 0,19 then it's already overlapping by 1 pixel.
You said you can't change it, but can you make a new condition that 'truly' act if an object overlap another one and keep the old condition the way it is right now and maybe change his name?
I really have no idea if that would be hard to make, maybe add in the future that feature? I think this would be very useful for more possibilities in a easier way.