I dunno, that was only a suggestion.
Wifey and I did the Disney Wonder trip last December. Wifey booked herself for the dolphin encounter (kinda expensive) and she loved it, While I watched her do it. Back then the prize for the Blue Lagoon Beach day was $35.00 per person.
Remember, if you do the beach day, you guys are gonna wisked away on another island about 45 minute boat ride. Lunch is included on that prize.
While on the Atlantis Resort thingy, you guys could take a taxi to get there. It is just another nice Hotel and Casino resort.