I bet in average you save 15%.

Just joking! I'd totally need a calculator in order to turn that into real numbers.
I am also booked for LM during the time period at issue. My question is a bit different:
Assuming the current promotion is extended, would it be worth it to upgrade to a moderate?
It looks like Carribean Beach is regularly priced at $195 during the time of my stay. Assuming a 25% room discount, that would be $146ish/night.
Is Carribean Beach mod stay at $146/night a worthwhile jump for us to make? I'm paying $121/night (if I remember correctly...) for AoA LM. Over the course of our 7 night stay, it will cost me $175 more to be at Carribean Beach.
This is our first Disney trip so I'm feeling like a fish out of water when it comes to these decisions. I'm leaning towards just keeping my LM room, but what do others think?