I was thinking it would stop running the old copy if the new one works out.
In today's practice, there are many copies made. Consider Google for instance. At any point in time they are running hundreds of experiments, to see what works best. They don't make one copy at a time for performance reasons. Exploring an adjacent search space is faster if you run trials in parallel.
Peter Suber is the Director of the Harvard Open Access Project, a Senior Researcher at SPARC (not CFAR's SPARC), a Research Professor of Philosophy at Earlham College, and more. He also created Nomic, the game in which you "move" by changing the rules, and wrote the original essay on logical rudeness.
In "Saving Machines From Themselves: The Ethics of Deep Self-Modification" (2002), Suber examines the ethics of self-modifying machines, sometimes quite eloquently: