Ovulation

This is my first month tracking my ovulation. I work 9-5 so am not able to test in the early afternoon. The first day I tested I tested late in the evening, almost 10 pm. The next day I tested as soon as I got home from work. Then again at 10 pm to try to keep it consistent. I found that at 5 pm I was lower than at 10 pm from both days, is that normal? Today I’m going to try and do it again. To have more days to reference to.