Upside down?
Well, i would strive to have them perfectly spaced.
PERFECTLY spaced
So that regardless of orientation of the bottom to the middle, it will latch.
I. E., if you have 3 latches it will lack in all three positions everything lines up.
That's if you're using the both sides of the latch.
If it will let under the lip of the bottom part, then it can latch in any position.
I think that's also why someone said install it "upside down"