Why would you wait until the 5th or 7th to modify? Wouldn’t your chances of being able to snag the remaining dates be higher if you keep adding each day on day by day (since you would be adding on dates prior to the 5th)? Or am I missing something or not fully understanding something?
Your reservation has that room off the table until the 7th, no one can book that room until the 8th, you gain no advantage by adding every day, you only make more unnecessary work for yourself.