The chart above shows how a 5% phase-out rate for a hypothetical family of four with two kids, with a $150,000 income threshold.
For the family of four, giving households $1400 rather than $500 extends federal benefits to families earning more than $226,000 but less than $262,000, even as all else remains equal.
For any given phaseout rate and income cutoff, higher benefit amounts mathematically guarantee that taxpayer dollars flow higher in the income distribution. Bigger underlying benefits phase-out only once you’re further past the income threshold.