My guess is that it would depend on whether you have a valid, complete OWA booking ticketed prior to the changes in August, or whether you have only booked part of a OWA itinerary. In the first scenario you should only be liable for changes in the surcharges, as is routinely the case at present. The points requirement shouldn't change after August.
If, on the other hand, you don't have a legit OWA booking come August, you should expect to have to pay extra points as well.
My thoughts were to book a valid OWA fare prior to the increase just to lock in the 318k cost and then amend dates and sectors to something I actually want to fly further down the track.
But obviously if I had to pay a fare difference there'd be no point in doing the extra work and dealing with what sounds like quite a hassle trying to get the call centre to process changes