This paper, and my post in reply, is about a question deeper than that, namely, why doesn't time itself run backwards sometimes, in essence? (That elides over some things, which unfortunately including the essence of the question, but there isn't a snappy English formulation of the problem that I know of.) Nothing seems to stop it, except inasmuch as it never happens so something clearly is.
What you're talking about is a foundation to that argument, but the argument itself is beyond that. While the physicist in question has hopefully considered the point I make, he certainly knows about the statistical nature of entropy. However, while that is necessary knowledge, it is not sufficient to explain the other mysteries of entropy that this paper is about.
I understood what the article was saying, but it seems I didn't understand what you were saying. If I understand it now, you are saying that to prove his case he has to not only show that entropy can't directly decrease by, essentially, undoing the process and getting back to the original state, but he also has to show that entropy can't decrease by the system ending up in a state different from the first, but yet which is also of lower entropy? It seems to me that you are correct.
What you're talking about is a foundation to that argument, but the argument itself is beyond that. While the physicist in question has hopefully considered the point I make, he certainly knows about the statistical nature of entropy. However, while that is necessary knowledge, it is not sufficient to explain the other mysteries of entropy that this paper is about.