I was wondering if your new Fusion was still running cool. A simple test for the thermostat occurred to me. Clamp off the hose leading from the thermostat to the radiator, then take it for a short drive. If the engine warms up quicker than normal, that indicates that the thermostat is stuck open.
They ran tests using their fancy $40K laptop, thermostat is working OK, according to it, but it is suspicious when driving @ 55 MPH and the temps are hovering around 160* for most of the drive, almost as if there is a bypass in the system. I am going to pick up some thin Lexan to cover the grill this weekend and see if that helps any.