I'm sure someone else will respond that has a better memory than mine, but if I remember right, you are correct - there is no complimentary sauna/steam room on the Oasis-class. We were on the Allure last year and I'm pretty sure there wasn't one I could use for free. I really like a good steam bath and appreciate it when they have one to use in the locker room.
Travel Agent/Cruise Specialist w/13 yrs exp and 48 Cruises on 11 cruise lines! Favorites: Paul Gauguin - Tahiti: Uniworld River Cruises - Europe; Celebrity Solstice-class ships; Holland America - 12-nights Baltics & Russia; RCCL - 14-nights Greek Isles, Turkey, & Croatia; Holland America - 14-day Alaskan cruisetour; 10-night Canada/New England cruise; 21 days Hawaii w/7-night NCL cruise; Oceania - 25 days in Asia; more than 3 months touring Europe by train. And many all-inclusive resorts!