You have very good questions, I can only guess one answer: s3 network transfer is free for AWS services Your link[1] said: You pay for all bandwidth into an

You have very good questions, I can only guess one answer: s3 network transfer is free for AWS services Your link[1] said: You pay for all bandwidth into and out of Amazon S3, except for the following: [...] - Data transferred from an Amazon S3 bucket to any AWS service(s) within the same AWS Region as the S3 bucket (including to a different account in the same AWS Region).