If your natural potential let you able to get 20 pound. You get 10 pound which mean you can still grow for another 10 pound .
Lets say you take gear and get 15 pound. Is the 10 pound you were stll able to grow easily lost or is he been replaced by the one with aas?
In a normal way you will have grown 20 pound easily and be at your full potential then u take aas get a 15 pound and ended up with 35 pound of muscle.
On the 1st part you have grown 10 pound easily get aas be at 25 pound , but your natural potential had 10 pound of muscle easily attainable left. Are they gone and you gonna have a hard time to reach the 35 pound of the second hypothesis??
P.S. hopefully its more clear