There is NO surcharge for the wristbands... At the CS, the room rate includes the room, and wristbands, for up to four people. (They seem to be strict about the 4 person limit.)
The small surcharges that you do see when you check the Comfort Suites site are taxes and 'energy surcharge' mandated by The Bahamas for all hotel rooms.
I understand that the Atlantis does indeed have a surcharge for older children... 12 and up??? 16 up?? not sure of the age... But the Atlantis does charge for older children as an extra-adult.
Hope this helps!