Of course the calculation was wrong. The correct calculation would require consideration of the entire tax code and every means tested benefit the hypothetical family might be eligible for. But your assumption that the loss of $45,000 rather than $65,000 makes it not a cliff is equally erroneous, because many of the other things not accounted for go the other way. The loss of financial aid may still exceed $45,000 for a family with more than one child in college, or if the housing expenses in question are eligible for some other source of means tested financial aid. The additional income may destroy various previously permissible tax deductions because of the Alternative Minimum Tax. There are any number of totally unrelated benefits that the family may lose eligibility for at the same time.

There is a realistic hypothetical family that loses more than they make in total regardless of whether the loss of Stanford financial aid is $65,000 or $45,000.