Hii

This is nothing to worry about. The percentile declared by NTA are not the final ones, the percentile are calculated shift wise, so it can vary for two different shifts. Also the final result would be declared after compiling the scores of both the January and April sessions, All shifts and best of two scores would be used for candidates appearing in both sessions.
It is likely that candidates in your shift, might have done better than those in your friends shift, So the percentiles vary.
Percentiles are calculated as follows-
100 * no. of candidates appeared in the 'session' with raw score equal to or less than the candidate / Total no. of candidates appeared in the session

You can refer to following link to know more about the Procedure of scoring and normalization.
https://engineering.careers360.com/articles/jee-main-normalisation-process-how-scores-are-calculated
Hope this helps
Thanks!!

Hello Brungeshwar

I totally agreed with the point you are facing but the percentile core is depend upon some factors in every shift

• No of students apper in exam in that particular shift.
  
• Percentile Score shows the percentage of candidates who have scored equal to or below a particular percentile in an exam.

for more information please read this article it will help you

https://engineering.careers360.com/articles/jee-main-normalisation-process-how-scores-are-calculated

I hope you get my point

Thank You and GOOD LUCK!!!