I highly doubt that the tax info. transferred from the IRS is different than the info. that was on the tax return as filed by your mother. If your mother’s tax return was correct as filed and you think your FAFSA EFC is wrong, there is an error somewhere else. Take kelsmom’s advice and “get in touch with an aid officer who knows their stuff.”
You mentioned child support income. That won’t be on the tax return, so it needs to be reported elsewhere on the FAFSA under untaxed income.
You can follow up with the FA office and have them check that the tax information they have matches the tax return.
Update:
I’ve spoken with people at colleges and with FAFSA today and I figured out the issue on my own. We were reporting way more child support than we received, which inflated my EFC a ton. Now that I’ve corrected that mistake and put in my W-2 accurate 2017 income my EFC is around 3700, something we can afford!
Thanks so much for all your help.