Chuck,
Mine also has a hole drilled in it about 1/3 the distance from the back. I also have no real clue as to why it is there. Like Eric I use gutter extensions and my front is usually slightly down. I also use a light weight plastic gutter splash guard that I angle under the coach and the water mostly splashes into it and drains away from where I step. If the wind is blowing then all bets are off.