If you are configuring a service and find that after setting a specific storage limit that the limit in the dashboard is higher then the set limit it is likely that the customer has another Audio Service. Audio Services in the Media Control Panel combine and share their storage across the account. Which would result in a customer with two audio services set to a 5 GB limit actually having a combined 10 GB limit.
You can read more about how Media is managed and storage is configured in our Audio Operation Manual: https://www.mediacp.net/doc/user-manual/audio/media-library/