I do not know what AA has on their 737-800s but the way this works is the operators gets 10kts as standard on a new Boeing. They can opt for 15kts with additional charges. You see this option on operators that utilize the aircraft at airports with winds that do not always favor the ILS runways. The Carribbean and northern Latin American airports are subject to this condition more than just about anywhere else in the world.
BTW, this 15kt option is available on most if not all current Boeing aircraft