For the question, I kind of still don't get it. I figured out that climb limit weight depends only on engine performance. But any specific reason as to why?
- because it is, by definition!
As an 'F/O' flying on 737s, you MUST have studied performance, surely, even in India? Where did you do your CPL licence training? Which airline are you flying with?
Why not tell us how you calculate the maximum weight that you can take-off with in your airline?