Total Household Income on Form 8962

Why must I declare my son’s income on Form 8962? He is a dependent on my tax return. But he doesn’t contribute to our household expenses. When I include his income on Form 8962, the repayment limitation amount on Line 28 goes up from $1500 to $2500, and the tax I owe to the Feds goes up by almost $1400 on my 1040 tax return. So it is costing me double. I get less premium help on my wife’s health insurance plan because of my son’s income, plus I pay more Fed income tax because of his income. This seems to clearly be the law, but…