Each accompanying spouse and each unmarried child under twenty-one adds a further US$15,000 processing fee and a further US$1 million gift, including where a corporate sponsor is involved. A household of four therefore faces four of each, and a child who turns twenty-one is no longer eligible to accompany.
Per person, and the clock runs on the youngest terms
The most common misunderstanding is that a single payment covers a family. It does not, and the difference between one set of figures and four is not a detail. The second issue is the age limit, which cuts hardest for households with a child in their late teens because the process is not instantaneous.
Ilse's elder child turns twenty-one within the year, and once that happens the child is outside the accompanying-family definition and would need an independent basis to move. Whether any statutory protection could apply depends on the facts and on the programme's current terms, and it is precisely the kind of question that should be put to a licensed U.S. immigration attorney before a nonrefundable fee is paid for anyone in the household.
Planning around a birthday is far cheaper than reacting to one.