Agree with Thumper1 - My D's college requires the FAFSA no matter what your EFC if you plan to take out any loans, e.g. Parent PLUS loans.
Check with your school's FA office/website - all the info is there!
Most schools use the FAFSA to determine any Federal aid (Pell grants, Stafford loans etc)using the "federal methodology". The CSS Profile is usually for college level aid, grants, scholarships. The profile uses the "institutional methodology".
Check-out the
:: College Planning Made Easy | Inside Source for College Admissions Requirements website and you can also use their financial calculators to check your EFC and compare the 2 different methods.
Our EFC was 23K and we recieved a significant "need" with grants and merit scholarships. My D goes to an expensive LAC - so for us it was worth it!