Hi Doug,
I have found that you need to do at least 2 star align if you are working in the close area of the 2 stars(i.e. S,E,N,W, if not, 3 star align gives the handset/mount a better idea of the complete coverage area.
If I do a 2 star south align, most things N,NW,NE are out slightly.
3 Star improves that again.
Hope this helps
Adrian