Hmm, interesting. When I wheel aligned my car Friday night, I set camber to 3.1 or so and then when I finished (after castor adjustment) it actually increased static camber to 3.25. Thinking about it a bit more pulling the LCA foward makes it a bit more parallel to the upper arm (as it's on a ~30deg angle facing backwards) and effectively makes it longer. This is just me thinking about aloud at the moment though...
Because of the angle of the upper arm, when you shorten it, it pulls the top of the upright towards the back of the car, so you increase castor by a fair bit aswell as camber.
Well this has been my experience anyway and me thinking about it a bit more makes a bit of sense to me, so good enough for me