I am not just formatting it, I am flooring your date. It seems that your Date_Started is just formatted as a date, but includes time information as well. So each instance of your date can have a different time which was showing up as a different row. When I used Floor, it was all grouped together into a single date. Does that make sense?
If you have got what you wanted, I would request you to close this thread by marking correct and helpful responses.