Dealing with Amazon billing is absolutely infuriating. We are also on their EDP (Enterprise Discount) program and all of it is done MANUALLY. There is literally NO way i can check hundreds if not thousands of instance hours to ensure there was no error in their processing. Its complete madness. We use a dozen services and EBS, Bandwidth, inter-AZ bandwidth is impossible to audit.
That being said we have Looker sitting on top of Redshift, we make sure each "team" has a tag (infra wont spin up without it) and then we can easily set budgets, watch trends in Looker and track spend by team and by product name. Our finance team loves it.
The data is there, but Amazon REALLY makes you do the work. Their default billing reporting is useless.
Will publish on HN when our tool is open sourced.