Confusing submission process

<p>On Common App, it says once the application has been submitted it may not be altered in any way.
I am done with the common app itself. I am applying to 4 schools. Two of them don't have separate supplements, and two do.
I haven't finished the separate supplements yet. Today or tomorrow, I want to go ahead and submit the two that don't have separate supplements. So, if I submit these two, does it mean I won't be able to finish my separate supplements for the other two schools?</p>

<p>The Common Application itself would be little difficult (but not impossible) to change, but you would be able to submit the various supplements just fine.</p>