The federal form and the Profile can ask about different parents, and that is the difference most likely to change what a family should do. Since the FAFSA Simplification Act the federal rule is narrow: for a student whose parents are divorced or separated and not remarried, 20 U.S.C. 1087oo(f)(2) reports "only the income and assets of the parent who provides the greater portion of the student's financial support." If that parent has remarried, 1087oo(f)(3) adds the stepparent's income. The other biological or adoptive parent is simply outside the federal calculation. The College Board makes no such promise about the Profile: "Some schools may also require divorced or separated parents to complete separate applications," and the fee-waiver page prices a separate noncustodial submission as its own transaction. So a family that has organized its expectations around the FAFSA rule can meet a very different question at a private college.
The noncustodial waiver is real, it is documented, and it is not automatic. The College Board publishes a "CSS Profile Waiver Request for the Noncustodial Parent" whose opening sentence is the principle behind it: "Financial aid eligibility is based on demonstrated financial need, not on a parent's willingness to pay for education." The form lists the grounds that may be considered: no contact or support ever received from the noncustodial parent, legal orders limiting that parent's contact with the student, and abuse situations. It also lists the two grounds usually not considered, which are the two families most often expect to work: a parent who simply refuses to complete the application, and a divorce decree stating that a parent is not responsible for educational expenses. Supporting documentation may include court orders and a third-party statement, "preferably a written statement or letter from a counselor, a social worker, a teacher, or clergy who has first-hand knowledge" of the situation, while "statements from family members or attorneys may or may not be accepted." Three limits are stated plainly on the form itself: submission "does not guarantee that a waiver will be approved," each institution makes its own decision, and another institution "may require their own waiver form and may not accept this version."
What the Profile produces is an input to somebody else's formula. Nothing in federal law binds a college's institutional methodology, which is why two colleges reading the same Profile can reach different conclusions about the same family. It is the point buried inside the phrase "full demonstrated need," which means the need whichever formula the college used calculates, and the practical consequence is that the only comparable figure across offers is the grant dollars each college actually puts on the table rather than the promises or the index.
Cost, and the waivers. The College Board charges a submission fee and publishes three automatic waiver grounds for a domestic undergraduate: family adjusted gross income below an income threshold it publishes, qualifying for an SAT fee waiver, or being an orphan or ward of the court under the age of 24. A waiver "cover[s] all application and reporting fees," and students find out whether they qualify while completing the application rather than by entering a code. Two limits are worth knowing in advance. A U.S. citizen living abroad is not eligible, because "a dependent student's custodial parents must live in the U.S. or a U.S. territory to be eligible for a CSS Profile fee waiver." And an SAT-based waiver reaches the custodial family only: the noncustodial parent is considered separately, on the information in their own application.
A related service that is not the same thing. The College Board also runs the Institutional Documentation Service, IDOC, which collects tax returns, W-2s and other documents and distributes them to the participating colleges that use it. Not every Profile filer is asked for IDOC documents, and being asked is a separate step with its own deadlines.