How does per GB billing work on S3 AWS?

Hello.
In such cases, calculations will be made on a pro-rated basis.
So I thought the fee would be further divided by time from the daily rate.

https://aws.amazon.com/s3/faqs/?nc1=h_ls

Storage Example:

Assume you store 100 GB (107,374,182,400 bytes) of data in Amazon S3 Standard in your bucket for 15 days in March, and 100 TB (109,951,162,777,600 bytes) of data in Amazon S3 Standard for the final 16 days in March.

At the end of March, you would have the following usage in Byte-Hours: Total Byte-Hour usage = [107,374,182,400 bytes x 15 days x (24 hours / day)] + [109,951,162,777,600 bytes x 16 days x (24 hours / day)] = 42,259,901,212,262,400 Byte-Hours. Calculate hours based on the actual number of days in a given month. For example, in our example we are using March which has 31 days or 744 hours.

Let's convert this to GB-Months: 42,259,901,212,262,400 Byte-Hours / 1,073,741,824 bytes per GB / 744 hours per month = 52,900 GB-Months

This usage volume crosses two different volume tiers. The monthly storage price is calculated below assuming the data is stored in the US East (Northern Virginia) Region: 50 TB Tier: 51,200 GB x $0.023 = $1,177.60 50 TB to 450 TB Tier: 1,700 GB x $0.022 = $37.40

Total Storage cost = $1,177.60 + $37.40 = $1,215.00