See basically when you fill in the form you do it on the basis of your preference. If you go for float, then you may get the option above. If you go for slide , then you may only get options which you gave in that same institution that are above. It's better to go for float as all colleges/branch are open which are above in your preference list. If you stick to your home state college then sliding is the best option. for more details follow the below link :