Hi cashthrowaway
First congratulations on acceptance, second a grant of that magnitude makes this in your reach and a great deal. Although USC is a 100% need school they use more than the FAFSA they use the CSS and their own formulas - remember it is their money they are gifting as they are a private institution and they actually don’t have to meet any financial need.
My advice like others is to go to USC take the loans you won’t be sorry it’s an amazing school.
Believe in yourself - the school does they accepted you out of 54,100 applicants and they also gave you a very good financial aid package.
To complain about a USC’s net price calculator showing that your the average aid might decrease seems a little disingenuous. With that said I would not worry about it net price calculators are not exactly what I would call incredibly accurate as every individual situation differs. If your situation changes you can appeal for more aid - I know they actually do take appeals seriously and I’ve heard of grant aid going from $5,000 to above $40,000 due to changing circumstances - they real do consider things. But USC will require a lot of documentation to make sure all parties are honest.
I do want you to understand if you attend USC there will be students sitting next to you whose parents have mortgaged their paid off home to the hilt to just to send there kid there who is receiving no merit or grant aid. Just food for thought.