Ahh nice work! Yeah I just read A Brief History of Time the other day, and I've been thinking about this a bit myself. It seems like an entirely plausible theory to me...

So what do you think about time? Based on this model, and some of what Hawking talked about, beyond point 3 Time would subjectively appear to go backwards as matter goes from a state of disorder to a state of order. I've just been thinking too - if everything remains constant, and this might be a bit of determinism really, but beyond point 3 each reaction should perfectly reverse itself... the entire events of the expanding universe would be repeated.