Hello, The cut off will usually  reduce compared to the first round also simultaneously only lesser number of seats will be available for counselling. For instance in Round 1 in College A Computer science department has 80 seats in open category and only 75 seats are filled and the 75th person has 988 rank. In round 2 the remaining 5 seats will be available and a person with 1200 rank may get it also rarely a higher cut off is also possible in the final mop up round because certain candidates with higher say 700 rank wont be allotted their preferred college and would participate in the final round and may secure that college A seat too.

Hope this helps.