If you dial in on Saturday and don't exit before 11:59pm then the time that you used on the last Saturday session will count towards the next week. For example if you dialed in Saturday at 11:00pm and then stayed online until 12:30am Sunday morning the timer will register that you have used 90 minutes and it will subtract 90 minutes from the 8 hours of your current week. To avoid this happening make certain that you logout and log back in at least 5 minutes or so before Saturday midnight.