I have three cards, for about three months now. I finally figured out the reporting cycle.
Each card has its own statement ending date (usually about ten days after payment due date). Whatever the balance is at midnight of the statement end date it what is reported
However, they report all cards on the last day of the month, regardless of when the statement end date was during that month. I usually make a small payment on the payment date, and then make a bulk payment on the day of the statement end date. Then, the almost fully paid off balance is what is reported at the end of the month. regardless if I max out the card between the statement end date and the last day of the month.
Hope this helps.