Within the validity period, VIP users can renew or upgrade the VIP service.
Renewal: The VIP level remains the same while the expiry date will be extended.
For example, your VIP will be expired in 5 days. If now you renew the VIP and order another month of VIP, your VIP will expire in 36 days (1 month + 5 days).
Upgrade: Your VIP will be upgraded immediately after you complete your payment. The expiry date remains the same.
Upgrade cost = (VIP price per day after upgrade – original VIP price per day) * remaining time of your VIP.
For example, the price of VIP (10% discount) 1 is 30 HT (1 HT per day) and the price of VIP 3 (30% discount) is 60 HT (2 HT per day). A VIP 1 user wants to upgrade to VIP 3 while his or her VIP will expire in 15 days. He or she needs pay the upgrade cost for the remaining time.
Upgrade cost = (VIP 3 price per day after upgrade – VIP 1 price per day) * remaining time of the VIP 1 = (2 - 1) * 15 = 15 HT.