See ... if u r not alotted your highest choice by the third allotment ..... u will be considered for upgradation ..... real time allotments are for those who have not been allotted any branch ... so they come and take admission in any of the branches where seats are available.... you upgradation is purely based on the number of seats ahead of u that are blocked by other candidates .... once they opt out or dont confirm their seats ... you will move up the waiting list and eventually get your choice....