Does need-based financial aid stack with National Merit Presidential scholarship at USC?

My son is interested in aerospace engineering and is a National Merit semifinalist. I ran the USC net price calculator and it showed “estimated gift aid” of about $40,000. This is much more than the half-tuition Presidential scholarship for National Merit finalists.

Is there any stacking of need and merit aid at USC, or would we expect to pay based on the net price calculator? (I’m not saying it should, just asking how they operate)

Second question- do outside merit scholarships stack at all? For example my daughter (at a different school) has an outside scholarship and she uses part of it to offset expected student income from jobs and to purchase a computer.

Sorry for question #1. I realize the answer is almost definitely no stacking.

At any college merit aid will reduce your need and thus need based aid.

If you’re eligible for more aid than the merit scholarship, you’ll likely receive eligible aid - merit scholarship = need-based aid. Outside merit scholarships will count against your aid after you’ve exhausted your student contribution (summer work + school year work + maybe a 1 time computer purchase.) Keep in mind that while the NM Scholarship is guaranteed, FA is an estimate, not a guarantee.