With a majority of BB'ing exercises, you can make a 10lb DB feel like a 100lbs, when accounting for the exercise system/style, performance or leverage. Even a twist of the wrist, different hand gripping, the path of the elbows during a movement can make a difference. Remembering that BB'ing is not a strength challenge, the old adage that get stronger and muscle size will follow is not always correct. Old motto in BB'ing was "more blood, more muscle" which the classic BB'ers of the 60's & 70's knew all too well.
When you see a massive Pro doing set after set of twelve and a half lb DB laterals (even getting out of breath doing them...which I have witnessed first hand) you got to take into account his success. Though spending $8- to 12 thousand a year for "helpers" has to be taken into consideration. Most of his reps were the swinging up kind, lot of body English..which most of the larger men do in most any exercise.
Being humbled by old man weights, used in certain exercises, can be something to overcome by most guy's. Ego can usually delay the full potential for a lot of folks. But the bottom line is results in BB'ing, no matter the workout system used......light, moderater or heavy. Just have to find out what works best for you.
Good Luck.