Basant & Josiah are transferring 8 TB & 4 TB of data into S3 in a month respectively. Basant’s AWS account is the Management account who’s consolidated bill includes Basant’s own Account & Josiah’s Account. How much of the total S3 cost will the Management account be charged for both accounts? (Given below are the charges for S3)
Price per TB (first 10 TB) = 0.17 * 1024 = $174.08
Price per TB (Next 40 TB) = 0.13 * 1024 = $133.12

Answer options:

A.174.08 * 8
B.174.08 * 12
C.174.08 * 10 + 133.12 * 2
D.174.08 * 4

Correct Answer: C
While using AWS consolidated billing, all the Accounts considered for billing are treated as a Single Account. The consolidated billing will appear in the Management Account (Basant’s here). Consolidated billing provides the advantage of having volume discounts which is provided by combined usage from all Accounts by AWS. It determines which volume pricing tier to apply providing a less overall price whenever possible. The calculations for arriving at the final result are as follows.
Price per TB (first 10 TB) = 0.17 * 1024 = $174.08
Price per TB (Next 40 TB) = 0.13 * 1024 = $133.12
Basant’s Management account will be charged with 174.08 * 10 + 133.12 * 2 = $2007.04
If the billing were to be done separately for both Basant & Josiah, $174.08 will be applied to both accounts and the resulting charges will be $2088.96 (option B).
Option A is incorrect since this will be only Basant’s Account charges
Option B is incorrect since this will be the charges without using consolidated billing
Option C is CORRECT since volume discounts are applied to the entire 12 TB of data transfer ($0.17 for the first 10TB & $0.13 for the last 2TB) due to use of a single billing Account
Option D is incorrect since this will be Josiah’s Account charges
Diagram:
Reference:
https://docs.aws.amazon.com/awsaccountbilling/latest/aboutv2/consolidated-billing.html