It is not always that you will get a better option in second  round of josaa though sometimes your seat may get upgraded as per your choices. It's all a game of rank and preference of you as well as all other candidates if your rank is good enough you will definitely get a branch uogradation in subsequent rounds provided candidates having better ranks than you get even higher preferences leaving lower seats vacant. So in short it's not a thing that can be predicted but it has to be watched as the results unfold.