I would imagine doing a deep dive for AOW to 65 feet in a lake or quarry with no current, etc. would be the only way in many locales that it could be done. And the shop will of course want to offer AOW. My Wreck course was done in fresh water (penetrating some boat-like object...). Could've been in the Gulf of Mexico. But even if they could drum up enough students to make it economically feasable, they usually don't have their boat in the water when I was there in March. LDSs want to offer the courses whatever way is possible in order to develop customers.