Well i am a bitsian, so i would like to point out a few points andthen leave it to you to decide
Firstly, what are the chances that an sc/st guy joins in bits. Its almost 1 in 100 if you ask me
So for an sc/st guy the fee in iit’s are very low and easily affordable.
Then in bits the yearly fee including food and all other things will round off to 3.2 lacs, where as in iit you have 2 lacs per year without the food and other things,and yes bits offer a lot of scholarship in tution fees according to your family income and your performance in the semester, not sure with the iit scholarships
The iit statistics may not be that accurate,as one guy cannot study simultaneously in both the colleges