Well given that hot toys doesn't give a firm date, and sideshow has no control over that as they are a store, not the manufacturer...but as said by another, if the estimated (and there's the key word, estimated) shipping date is missed sideshow generally refunds the NRD. The same issues with the product being not what you want. That's not something sideshow controls. And the proto shown states it can change and is not final.
If you don't like the NRD then wait till the figures released. If you can't afford 10% then you probably in the wrong hobby. It's a perk provided by sideshow. They very well could require full payment. Sideshow bends over backward for fans. Flex payments. Preorders. Actual customer service that's not just available, but great.