I left blank lines between my paragraphs on my AMCAS app. I think you could go into your app and make that change without it affecting your submission date. (You might want to check with AMCAS before you do that, but I did make several changes after I submitted with no dire effects). If you don't want to risk it, you should be able to do a cut & paste and recopy job that would be hardly noticeable. I did that with the list of schools section, because I didn't want all my schools to see the whole list -- or even the amount of space the whole list would have taken.
