Hello student,

The variation between ranks in first phase and second phase will depend on the number of seats left after first phase of counselling.Some times there will only be a variation of 500 rank but if more seats are available in the college,the variation of rank might even be 1000 or 2000.These mainly depend on the number of students who are happy with the result of first round (so they dont participate in second round) and the number of students participating in 2nd phase of counselling.

for more details please refer the following links-

https://engineering.careers360.com/articles/ts-eamcet-counselling

https://engineering.careers360.com/articles/ts-eamcet