The information on the Wasabi management console Billing tab is intended to provide the user with info pertaining to their usage of the Wasabi Service. To better understand the info on the Billing page, let's consider the example below.
Usage example parameters:
User starts a trial with Wasabi on 1 Sep 2020 and uploads 500 GB of data on this date
On that first day, user also deletes 40 GB of data and replaces it with 40 GB of other data
Now, if the user checks the Billing page on 15 Sep 2020, they will see the following:

More details on these pricing terms can be found at https://wasabi.com/pricing/pricing-faqs/