Can you get a flashing smiley face and then a solid smiley face in the same day?

Hi, I’ve just got my third flashing smiley face, and from my calculations I should ovulate tomorrow... but saying that its not works so far so maybe I have no idea. Anyway. I’m just wondering, should I test again this evening in case this changes to a solid face? As I’m guessing you can ovulate any time, like at night so I could be losing 12 hours??