Yes, the EFC I got from Collegeboard, spreadsheet and EFC formula was the same in our case.
Collegeboard EFC calculator doesn’t ask about siimplified needs or tax form used, but it asks about means tested benefits and dislocated worker, two other qualifiers for simplified needs test.
Starting in 2018 tax year, there won’t be a 1040A or EZ anymore, we don’t know what that will mean in regards to simplified needs test going forward.
If you are going to amend parents’ 2017 tax return, take the 1098T and tuition statement for 2017 with you too and see if your parents could have claimed AOTC for you and your sister, and if you and your sister will end up having to file a 2017 tax return as a result.