I think you will find that most instructors, myself included, do not try to track what time of day sales appear on our revenue report. I track sales from month to month and other than that, I don't really care what time they appear on our report. But, maybe someone else does.
When it's your first course and you are getting a few sales per week you'll be looking for patterns, freak out when those patterns break or you have a day with no sale. All of this goes away after some time. There are no patterns. Trust me.