Usually colleges want documentation that something like this has already happened. This is because…it might not happen. You noted this yourself…it might not happen at all.
Contact the Wellesley financial aid person and ask what to do in this situation. They will tell you.
Being self employed or owning a business is one thing that often makes the net price calculators NOT accurate. And MyIntuition very often gives a lower net cost than anywhere else.
But the thing to do…speak to the Wellesley folks again. They will advise you what to do.
Do this quickly because it’s an ED2 acceptance.