Well if you are an SC candidiate by luck's grace then I think you should be concerned with your JEE advanced SC rank only.

Now with 150 marks and under SC category you have performed exceptionaly well. I can't tell much about the rank under SC category but that's for sure you are getting a pretty decent IIT.

One thing I would like to add that for general category with 150 marks, he won't stood achance of getting a seat at IIT 

All the best!