I also had to take a year off from in college due to getting sick. I did not write an extra addenda - there is a box in the education component of the app that asks if your education was interrupted for any reason, and I just filled that out. I wrote about 3 sentences saying I had to take a medical leave of absence which resulted in my education being interrupted for a total of two semesters. This is also denoted on my transcript by the courses I had to withdraw from. I didnt think it was necessary to go into the details of my illness for purposes of the application, particularly since it was medically related

I'm kinda in the same boat - also did not do as well on Dec 16 as I was averaging. I hit submit already, so I'm going to be sending out emails informing the schools I will be sitting for the Feb exam. I guess whether they decide to wait evaluate my app with the Feb score is really up to the school. Fingers crossed!

Should you indicate on your apps that you are registered for the Feb test? Even if there's a chance you won't end up taking it?