That happens. Since the exercise is self-reported, a lot of it has to do with how you're feeling as you are taking it, how you "interpret" the questions for yourself, etc. It's for information. Perhaps you've had a slightly more stressful time of it since the last time you took it. I only take it every 3-6 months, it's kind of a self-check thing to better help me understand what I'm thinking/feeling.