Your assumption is wrong. Need-based awards will not vary because one applies ED. That holds for all colleges.
Every other school has the exact same rules - ED is binding except if the FA is insufficient.
However, the applicant (and parents) need to do due diligence and run the Net Price Calculator to estimate aid. For domestic applicants, unless there are exceptions specified by the college (self employed, rental income are common exceptions. Divorced parents may be an exception depending on the college), the NPC shouldn’t vary from an actual award offer. If the situation is an exception, the FA office may give guidance or provide a pre-read.
On another note, you should change your username. This link tells you how.