Babs44 - welcome to LCT! It seems like the Paul Gauguin is selling out quite well this year and my guess would be that it is best not to wait until you might see a new discount. RSSC changed their marketing this year and have tried to make it so that the people who book the earliest get the best deals.
We booked our 2004 trip on the PG in 2003 with our fabulous cruise consultant Ngaire. She was able to phone us shortly after we made our required final payment to inform us that our weeks had just been discounted and she put through the refund on our charge card. So if you book with a good agent and the cost of your cruise goes down, you will get a refund.