For the vast majority of FT forum readers that don't live in China, the train ticket cancellation feature would not have been commonly used and so wasn't a particularly important phenomenon to deal with. The expats on this forum mostly already know about it, whether or not they've used it. IIRC it hasn't ever been dealt with in detail here, so not much of a priority to report on changes. I certainly have used the system to book myself more than one sleeper ticket where the exact day was unknown, with the intention of cancelling and returning the unwanted one usually day before the ticket departure date. The 5% surrender fee on a standard, non-HSR sleeper was a bargain, which I considered cheap hedging strategy when uncertain of timing was a problem that couldn't be resolved until real-time in the field. For instance, buying a second soft sleeper ticket for RMB 300 and returning it was only an RMB 15 penalty. Of course this rather generous policy had to get tightened up at some point. I think the new, prorated fee based on cancellation timing is fair, but I doubt if it will result in significant change in behavior. There are plenty of Chinese train travelers to whom a 20% penalty esp on standard trains--which is where most of the sell-out problems and supply/demand mismatch occur--isn't going to change behavior all that much. Sometimes you just don't know your final schedule or ticket usage, >48 hours in advance.

On the other end of things, and regardless of the cancellation timing, for people trying to get those last minute ticket returns, it's still going to be a crapshoot as to whether any tickets are returned into the system or not. Whether trying 2 hours, 8 hours, or 48 hours before departure. I don't think there's any general conclusion one can make about last minute availability potential, based on these new changes.