specific snapshots factors contributing to the cost escalation

How to find the specific snapshots which is causing the cost increase while being copied to another region via AWS DLM AMI policy ? EC2-other and EBS snapshot copy operation is causing the cost increase with the data transfer, but couldn't dig further to find the exact snapshots as the tag is only at the AMI end but not with the snapshots. Cloudtrail has limited details as well. Any guidance is appreciated. Thanks.