.. whether the paper was 1st sitting or second sitting ..
Are you referring to 20th Sep and 30th Sep batch?
Yes the papers on the 2 dates were different so the weighting for them will be different. A score of 40 on the 20th English paper would not have the same weighting as a score of 40 on the 30th English Paper.
Also with each paper on the same date the weighting will be different, a score of 40 in English will be weighted differently to a score of 40 in Maths. Every individual paper has a different weighting according to it's difficulty and what scores the people who sat it got. There's further explanation on other threads on here about standard deviation it's a complicated calculation.