Royal Ship Excursion

Question: We are planning to do a ship excursion in Dominica. The two I am interested in are ROC6 Emerald Pool and Beach; stops at Morne Bruce, Botanical Gardens, Emerald Pool and Beach time. This tour is 4:45 minutes long and costs $49.00@. Other tour is ROA7 and described at Emerald Pool and Volcanic Sand Beach. Described as going to the exact same places but names Mero Beach for the beach. Duration of this tour is 5 hours and costs is $59.00@. Aside from the obvious time difference of 15 minutes longer and $10.00 more per person is the only difference that it list Mero Beach vs. another beach? Anyone done either of these tours care to comment? Thanks!