I checked a bit later this afternoon, and was pleasantly surprised to find the reposted RPU, which I immediately applied to another flight, which had R availability, so I was instantly upgraded!!! Very pleased! Why I had expected 24-48 hours for reposting, I'm not sure, other than the agent did not every say that she had SPOKEN to mileage plus, only that my reposting was in the queue to be handled soon. In this case, it was almost an instant reposting.