Just a reminder as we enter the Black Friday season...
Prices are Prices.
Discounts do not exist, they are just different prices. If a discount is advertised- that's already baked into the price displayed. Royal creates a price and works backwards to create the fare that's discounted. No matter how big the percentage is, that doesn't mean it's a good deal or cheap.
Buy the extras you want if it looks like a good price. If the price goes down you can cancel it and buy it again. If it's the entire cruise, you can rebook at the lower price until the final payment date.
"It was on sale" is never relevant to the decision to buy something or not. Pick the extras you want based on their price and how much you're willing to pay. It's not relevant what the price was last week or next week, as you can always get the lower price.