Hi,

According to your  percentiles, the best score will be the percentile for March session i.e  75.

Cut offs for the year 2019 and 2020 for OBC category were 74.3166557 and 72.8887969. Also, the expected cut off for JEE advance for this year is 70-75 percentile. On this basis, your son could have qualified for JEE advance.

For more details you can refer to this link: https://engineering.careers360.com/articles/jee-main-cutoff

Also, you may refer to the college predictor link to get a personalized report for the colleges he can get into:

I hope this helped you.