Are you saying they don’t measure what you think they should? (If so, what do they measure and what do you think they should measure?) Or are they physically weak in terms of fatiguing first in bigger exercises?
Presuming it’s a measurement thing… in your shoulder width thread, you said you were “5’8-5’9 157 lbs”. Any chance you can post a pic? I have a feeling you either might have a skewed perception of yourself or you’re focusing on the wrong things. (Leaning towards the latter)
Stick with working towards gaining 20-40 pounds, like you mentioned in that thread. As long as you increase total body strength while gaining the weight, your “weak points” will become much less of an issue.