But your universe simulation is so in tune to the parent universe they're already doing the same thing. What you interprets as free will is the averaged respons

But your universe simulation is so in tune to the parent universe they're already doing the same thing. What you interprets as free will is the averaged responses of all parent universes. Not averaged. For example, the chain of universes may follow an alternating sequence: Mary in universe N kills Hitler in universe N-1 (one layer down). Suppose that this murder has the unfortunate side effect of preventing the birth of the Mary in that universe. The Hitler in universe N-2 therefore survives until 1945, allowing the Mary in that universe to kill Hitler in universe N-3. Ad infinitum. What we're dealing with here is stability. The average Hitler is half-dead and the average Mary half-born. The stable Hitler is dead half the time (in all odd universes); the stable Mary alive half the time (in all even universes). In fact, even stability is probably not the correct term. Let's broaden our scope. The Hitler example is just one cycle, of length 2. But there may be many cycles, of arbitrary length, from 2 to 3 or 10 or a million universes long. These cycles that interact will almost certainly do so chaotically. The odds that stability will occur is remote.