“I thought that if you are self-supporting and do not have a “custodial” parent, you used the biological parent with the highest income.”
Wrong. Tough way to learn that lesson. It’s “if the student lived with neither parent more, then it is based on the parent who provided more financial support to the student.” https://www.edvisors.com/ask/ask-the-edvisor/fafsa-student-doesnt-live-with-parents-02-2015/
So dad not only got a big income bump, but remarried, bringing the spouse’s income into play.
Sounds like they gave OP the Professopnal Judgment form. Please learn what you can, in order to make the best case you can, in the right ways.