You mentioned that your income will decrease when your daughter graduates from high school due to her Social Security payments ceasing. I hope you didn’t include untaxed Social Security payments as either her or her father’s income on the FAFSA.
https://fafsa.ed.gov/fotw1920/help/faadef33.htm
https://fafsa.ed.gov/fotw1920/help/faadef33.htm
However, it is possible that untaxed Social Security income has to be reported for Cal Grant purposes.