But child #2 has an undergrad degree? That does make a difference. That is one of the questions, are you seeking a first bachelors?
Either that or the information is not the same on the two forms. It can’t be and have that big of a difference if everything else is filled in the same.
The colleges on the FAFSA don’t matter at all. You don’t even have to list a school and an EFC will be calculated.