The CARES Act (text here), section 2201, provides economic stimulus payments. It provides that individuals get $1,200, and joint filers get $2,400, plus $500 for each qualifying child (16 or under). It also provides an income phaseout that reduces the credit "by 5 percent of so much of the taxpayer’s adjusted gross income as exceeds" a certain level -- $75,000 for single filers or $150,000 for joint filers. This means that, without children, one's payment will reduce to 0 if one's AGI exceeds $99,000 ($75,000 + $1,200 / 5%) for single filers, or $198,000 ($150,000 + $2,400 / 5%) for single filers.
My question is, how would this work for a family that is filing jointly with two dependent qualifying children? If their AGI is below $150,000, they receive $3,400 ($2,400 + 2 * $500). Does their payment still reduce to 0 at an AGI of $198,000, or does it slowly reduce until an AGI of $218,000 ($150,000 + $3,400 / 5%)?