Why do we see discrepancies in data between FlexReports and the S3 Usage report?

Products

• CloudHealth

Issue/Introduction

 

The S3 Usage report converts each daily line item to the actual amount seen that day.  This amount is rolled up to the month and then it is averaged.

FlexReports, on the other hand, just sums up the line items.

These calculations should be close but due to rounding issue they will likely differ.  At scale, when these rounding errors affect a large number of buckets we would likely see a small difference.

Ultimately, the FlexReport result will likely be more accurate as it's pulling metrics directly from the bill without additional manipulation.