A larger payment does not purchase an earlier immigration date. Classification can affect the applicable visa allocation, but the family still needs the correct category and chargeability review, available visa numbers and individual eligibility. Resolve the project’s claimed basis before using its advertised timetable to plan relocation. The assumption underneath the question deserves to be named: that money accelerates a queue. What actually moves a family's date is the priority date, the category, chargeability and the availability of a visa number, and none of those responds to the size of the cheque.
Update the family calendar when classification changes
Keep the principal’s filing plan alongside each child’s birth date and any age-protection analysis. Ask whether a different classification changes the availability assumptions used for the case, rather than simply adding US$250,000 to the same schedule. A spouse and unmarried children under 21 may qualify as derivatives, subject to the actual rules and admissibility.
The petition alone gives no US residence or work permission. Plan around the child whose age sits closest to the limit and let everything else follow from that. Have counsel run the age analysis on the actual facts before any figure is committed, because a structure chosen for financial reasons can shift filing dates and therefore shift the analysis.
Where a derivative may age out, the question is not whether to invest more but when to file and what protection may apply. Keep the family's dates and the project's dates on a single page.