The theory is sound, but execution can be troublesome. What counts as "income" is tricky and sometimes contradictory. If your AGI is below $50k and you can file 1040 a or EZ, yes, you meet the simplified needs test and they ignore assets. We meet the AGI part (thru 401k contributions), but we have an HSA, so must file 1040, but our income to family size qualify us for free/reduced lunches, another way to qualify. If AGI is below $24k (I think) and same as before, then you qualify for an automatic EFC = 0. That threshold is down from the $32k it was a few years ago - we easily hit that one, but no longer.
After that test, your retirement contributions are added back in, as well as tax free income (like Roth withdrawals!), as well as subtracting out certain costs: taxes paid, SS paid, employment allowance, living allowance. Anything left over is considered allowable income, and a percentage is assessed as your EFC. Then your child's income and assets are assessed.
Google "EFC formulas" and "paper FAFSA" to get the links to compute it on your own. The paper FAFSA is to see exactly what inputs they want in the formulas. Start on page 9 in the formula booklet. The allowance charts change yearly, and for some reason the savings protection one especially seems to shrink rather than grow with inflation.