technically, you're only getting alignment fixed for once....
yes again, you do need to take your car in twice for alignment.....first time is just to see how much your alignment is off....many shops do not charge a dime just to give you spec.
with mine, i knew mine was over -2.5 or more off because of tire wear i saw on mine compare to other frnd's camber wear on theirs.
oh and also, you can only assume how much your camber will be off based on your drop.....it varies on every car....