Yes Amrita University accepts JEE MAIN scores. You can rely on ranks more than the percentile because marks and percentile cutoffs keep fluctuating from year to year as they depend on various factors like number of candidates appearing and also the paper level difficulty, etc.

So I'll guide you with the cutoff ranks in various branches.

1. Civil Engineering - starting rank 6899 and closing rank 20001
2. Electronics and telecommunication engineering - starting rank 2698 and closing rank 15989
3. Chemical Engineering - starting rank 7791 and closing rank 19702
4. Computer science - starting rank 1821 and closing rank 13799
5. Mechanical Engineering starting rank 6895 and closing rank 17702

Refer to the link below for more detailed information for knowing the cutoffs of all the branches of previous years.. https://engineering.careers360.com/articles/aeee-cutoff