Do I need C&F addendum? (interruption of education) Forum

[nkime]

Hi, I'm an international applicant and I took one semester off before graduation, to prepare LSAT full-time.
Some schools ask on the application whether my education had ever been interrupted for a term or more.
I think I should answer "Yes", right?

In this case, do I need addendum to explain my situation?
If yes, is it okay to write just one sentence in my addendum? (see below)

"In regard of the question about an interruption of one or more terms in the education, I had voluntarily taken one semester off, 2011 Spring semester, to study for LSAT."

(The problem is, even though I took one semester off, my LSAT score is not high enough.)

[Swimp]

Yes, you need to explain it. No, you don't need to go into a lot of detail.