The number that NPCs spit back out is the Cost of Attendance (COA). I prefer to look at the billed costs (tuition, fees, and room & board) from the COA rather than just the COA because different schools are more generous in defining the same types of costs (books, allowance, travel, etc) than others. So two schools might both come back with a COA of $40k, but one would have direct costs of $38k with $2k in other expenses, while another might have costs of $34k with $6k in other expenses, which is really not the same financial cost.
This short thread may be helpful: Understand What the Cost of Attendance (COA) Means