While Kellogg is not rolling, they do release decisions starting about a month before the decision date for the round. Applications are reviewed randomly, but your application is not added to the pile until your interview is completed. So while it's certainly possible to interview early and still get your decision late in the round, you also have a better chance of hearing sooner if you interview earlier.
That said, you should schedule your interview when you feel you are best prepared for it. I'd rather get my decision later and know I presented my self as best I could, than rush my application/interview just to hear my decision sooner.