No. The published terms apply per person: each eligible joining spouse and each unmarried child under twenty-one adds a further US$15,000 processing fee and a further US$1 million gift, including under the corporate framework. Eligibility for a child depends on age and marital status, not on household budget.
Count the people, then check each one qualifies
Hypothetical example: Bronwyn's Callander household is two parents and two children aged seventeen and twenty. For a household like Bronwyn's the difference between one payment and four is decisive, and it is the first thing to establish. Beyond arithmetic sits eligibility.
The published wording describes unmarried children under twenty-one, so a child approaching that birthday introduces timing risk into a plan that otherwise looks purely financial, and a child who marries falls outside the description regardless of age. A twenty-year-old at the start of a process may not be twenty by the end of it. Families in this position should ask directly, before committing anything, how the program treats a child who ages out during processing, and should confirm the answer against official material.
Where a child cannot be included, the alternative is an independent route for that person, planned separately and usually well in advance. It is also worth writing down, before any payment is made, which family members the household would be prepared to move without, since a plan that only works if everybody is included has a single point of failure.