What they’re telling you is that they will reduce your “full ride” to cover any expenses not covered by the outside scholarships. Review the other scholarships, to see how they are intended to be used, and whether they are awarded specifically for your freshman year, or if they are less restrictive. Your school has no intention of “paying you” to attend the school, their intent is to help you attend.
Others here are right - you will have to pay tax on any scholarships above the cost of tuition and fees, plus books (qualified expenses). With the full ride alone, that includes room & Board, probably enough to put you in the 25% tax bracket (as a dependent, unearned income is taxes using estate/trust rates). If you take the route of finding ways to make school more expensive for the same of keeping excess scholarships, you will add more cost for yourself in the form of those taxes. Not a good idea.