Having a more accurate NPC is valuable to both the school and to the students and their families.
For a student to go through the trouble to apply, and then get an unaffordable offer, is a lot of work for the student, significant work for the university admissions, and lowers the university’s yield.
So I think that this is a plus. Having the parents (or whomever is filling out the NPC) provide a bit more information is I think worth the effort to get a more accurate estimate of the cost of attendance.