The whole concept of applying ED is based on the fact that the family has done their due diligence regarding finances (whether they are comfortable being full pay or accepting the financial aid offer), the school is the student’s clear first choice and that in exchange for an early decision, if admitted, they will attend. While one should use the net-price calculator to gauge, affordability, it is my no means a perfect process especially for families with complicated financial situations; stepfamilies, divorced separated, single parents, people who own property outside of their primary residence, self-employed, business/far owners.
While you don’t have to be married to the school for 4 years, you need to consider how you are going to finance it for 4 years. It is one thing to have 2 kids in college who are juniors/seniors when your child applies as a freshmen and you have this great financial aid package. But will it still be affordable when you have 2 kids in college or yet when that child is the only kid remaining and you may be full pay for the last 2 years? You may want to run the NPC a number of times each year adding an addition 3% to your income and 5% to the cost of attendance (as at many schools the price does increase every year). Don’t assume that because you have multiple kids in school that all things will be equal. For example if your FAFSA EFC is 25k per kid, and one kid attends the local CC, for 8k a year, your EFC may not necessarily be 25k for the kid looking to attend the 65K/year school.
One should not go into ED with one eye open, looking for the out clause or wondering what else is available . To me, you are expressing uncertainty and would be better served applying RD. Also keep in mind, what the ED process is at your school. If you need to compare packages or search for merit $$, which is a disadvantage of applying ED, then you should apply RD.
Student, parent and counselor all sign off that family agrees to and understands what they are getting into when they apply ED. ED also states, that you will withdraw all application and not make any new ones. At my school, when a student is accepted ED, with exception of rolling admission at local state U, the application process stops until the high school receives written confirmation that they have been released from ED.