Most of the aspirants of 18 March Set 1, find a discrepancy in their Percentiles when compared to the acquired Marks. I personally believe, their are 2 Factors which led to this

1. Comparatively easier Session

2. High Competition, with Aspirant getting better with each test.

3. High number of Students securing between 90-120/300.

You Percentile in JEE Main, not only depends on your Score out of 300, but on the Paper Toughness, Relative Difficulty and Competition of your Session.