For our Norway cruise last May, not too many weeks before departure, I noticed that the Vista suite was less than what we paid for a regular verandah. I called my big box TA and had them ask about an upgrade. Nope, nothing available. Duh-I called again asking for an upsell, knowing that the price was actually less. We got the Vista and kept all our perks, including the OBC, at no extra cost. We didn't receive any credit for the drop in price but I was happy with the nicer cabin.