Billing is calculated on a monthly basis, starting from 1st to the end of month (30 or 31st).
If the storage exceeds the billing month's assigned limit, overage is charged.
For a given month, data storage limit is fixed and not incremental.
Any exceeded consumption during a month is considered as overage.
Consider the storage as a Hard Disk. and you have 1TB of space.
You have consumed 900GB in the first month of your subscription.
Then you will just have 100GB remaining (from 1TB) for the subsequent month.
To make use of the allocated storage, you need to make space by deleting files added in the previous month.
Please contact us for volume discounts.