When you switch plans, it resets to a new billing date from that day and charges the difference for the following 30 days.
For example. If you have paid for 30 days on the 5th of the month and switch plans on the 15th of the month. The system resets your new billing day to the 15th and charges the remaining difference of 10 days. This means that you are charged for the additional 10 days of the following month (5th to 15th) to make up the total 30 day advanced fees.
