Mind if I ask which surgeon this was? PM is fine with me if you want. I can think of several reasons, but knowing who the doctor is might help me clarify my thoughts.
Also, I've heard several guys tell that they chose the size they wanted. Hopefully a conscientious surgeon would listen to their patient's wishes in regards to the desired size of the penis.
Worth mentioning for anyone who might read but not know, swelling can be pretty intense and make things look... well, you get the point. I'm think a fair number of pics available to view are taken early on when swelling might still be a factor in the apparent size.