The reason for that particular shape, I must admit, is purely aesthetic. However, I believe the majority of losses occur at the midpoint-to-trailing edge area. I didn't think the possible benefits of a forward overhang outweighed the aesthetic drawbacks, as life's too short to fly ugly planes!
I also have a similar set of plates on a Sig Ninja, that I've powered with a Norvel .074, and My flying buddies thought enough of them to add them to their Combat Gremlins...