AWS Charges for SAP CAL Instance

Dear SAP,

We are looking to subscribe SAP CAL instance "SAP S/4HANA, on premise edition 1511 FPS01 Fully-Activated". However during trial period we observed that AWS is charging huge bill for EBS volumes even though CAL instances were down all the time.

Will AWS charge for storage of EBS volumes, per hour based on amount of data when we subscribe to CAL instance?

If yes - is there a way we can limit the amount of data on CAL - so we don't end up paying huge bills to AWS for un-used time?

Please do advise ASAP - as we would want to move ahead in the process quickly.

Best regards,

Kalyan.V