[admin]

Basically the idea is to move as few points as possible to get the outline to roughly match up. There are many anchor points so that there will be a point you can move, close to any errors. i.e. if there wasn't a an anchor point on the chin and there was a problem there you would have to end up moving lots of other points around in strange directions in order to correct the chin. You can get pretty good results without worrying about this kind of thing, but these comments were added to the help file to stop people spending ages fiddling with points, which takes time and degrades the final result.