Zing started getting Megatron in stock in mid-August when it was scheduled to arrive on 1 September, so it's not impossible for Jazz to show up a week or so early, especially if it is showing up overseas.
TakaraTomy have finally revealed their release details for Jazz, which is also in early November, which isn't very long for a Masterpiece pre-order.
10,800yen (about AU$150).
Well I received notification from Oh My Primus that MPM Jazz has arrived and a quick check shows some stores have also got him.