Each and every boards in India have different top 20 percentile.For calculating top 20 percentile for different class 12th boards, the marks scored in five subjects - (1) Physics, (2) Chemistry, (3) Mathematics, (4) A language and (5) Any subject other than the above four, is taken into account.
If candidates have taken more than one subject (any subject other than the above four) as the 5th subject in class 12th, then also the subject with higher marks will be taken into account.
Last year Top 20%ile of Maharashtra board is 361 marks.
You are within top 20%ile.
All the best.