I'm not sure what you mean by "lean against the corners" Can you elaborate?
Putting the palm of your hand right on the corner of the cabinet, and supporting some of your upper body weight with it.
They put the metal corners on real pins to keep them from wearing out at that spot.
The location may be fine on yours, it just looks too far back in the drawing.
This is probably due to the CP not being as deep as the commercial stand-alones.
(Slik-Stik, Hot Rod, etc...)
Just double-check it for comfort BEFORE you drill the holes.
Plugging and redrilling is a pain you don't want to experience.