Ok, Steve supplied additional info from my initial computation. Thanks Steve.
For those in question, these wall warts are mostly constant power chargers. Therefore, as the cell number/voltage decreases from the rated amount the current will increase. Inversely, as the cell number/voltage increases from the rated amount the current will decrease.
Still, due to the limits of the wall warts it is a good idea to check the output with a meter and watch it for overheating. (The latter is just a safety precaution.)