Front suspension takes a "set" when you jack up the car - which is why you can NEVER allow anyone to jack up the car for an "inspection" before doing an alignment. If they do an alignment after jacking up the car, you will wear the inside edge of your front tires down to the cords in less than 500 miles. Ask me how I know. Alignment shop jacked up my car before aligning it - after being told not to. They ended up buying me two new tires...

As Alan pointed out, you have to drive it a fair distance for the front suspension to return to its static ride height.