RE: Why is the bottom left target the worst?
Okay, seriously,
Do you shoot them in order, 1, 2, 3, obviously 1 being your lower left target thusly your first arrow?
Not unlike a golf swing, muscle memorie in your shot sequence would normally make your best shot the 3rd arrow, IF your mental game is on. Think about it this way, your going up, pulling your arrows, coming back and shooting your first arrow each time.
IF allowed, switch it up and shoot the top target first, the lower right second and then the lower left and see if your worst changes.
If your not shooting in sequence, then disregard this post unless your shooting the same each time, switch it and see if it moves.
Just a thought.