Your guess is as good as mine.
From my testing, pathfinding is more or less inconsistent due to CPU issues. I can tell because when my enemy ships are pathfinding, a yellow afterburner sprite appears behind their engines. When they are moving due to bullet behavior (the default behavior I gave them), this sprite does not appear.
I am currently having them 'pathfind' every 1 second, but I'm not sure that is optimal. I'm thinking of removing pathfinding altogether and giving them a set AI behavior, in particular the rotate-move-rotate-fire
behavior I am trying to set up that I didn't get many responses on.
I am starting to think that pathfinding by itself is not really a good behavior to use, but instead to be integrated as a small part of an object's behavior for solving the problem of how to get from position A to position B.