Are you sure the school says it meets 75% of need of each student, or that in general it meets 75% of the need of students? Very different.
If the first, it could be met through merit or need based aid. Student needs $40k, school will give $20k in merit, $10k in need based (or loans). $10k unmet = 75% of need met.
If the second, you have no way of knowing how much of your need will be met. For some students, the school will meet 100%, for others 50%, for some 0%. You can’t know how much of YOUR need will be met.