Hi.

This depends on

1. number of candidates from each category
2. marks obtained by the candidates along with their ranks
3. seats allotted to each category in the given college.

Let's say that there are 20 seats in the given college allotted to the EWS category and the marks obtained by the 20th candidate fulfilling the requirements are 500. On the other hands if there are 50 seats for UR category and the marks obtained by the 50th candidate are 495, you can see that the cut off for UR is lower, as opposed to what you are saying. It can be vice-versa as well.