I think they meant while you submit the CSS profile once, and it goes to a number of schools, many profile schools will ask for supplemental information.
being declared independent due to legal guardianship for FAFSA only schools, does nto necessarily mean that you will be deemed independent for CSS profile schools or that schools that are generous with their own institutional aid. This is especially true if biological parents are still alive and the family situation has not been irreparabily broken as people get legal guardianship for a number of different reasons.
I do think that some people are oversimplying this has it can be a long drawnout process, whith different schools asking for different pieces of information,