What happens if I upgrade or downgrade in the middle of a billing cycle?

If you upgrade or downgrade the unused portion of your current subscription will be taken into account. If you have enough credit, you will not be billed, If your credit is not enough for your target plan you will be charged the remainder. Your new subscription will start immediately.

If you still have credit left even after paying for the target plan, your remaining credit will be converted to extra bandwidth and added to your account. (This is a measure we have to take because PayPal doesn't allow us to give you store credit)