Github Actions API - billable does not match billing information

I am trying to calculate the billable minutes spent on Github Actions for my account by querying the API.

I have only one repository that uses Github Actions.

  • When I send a request to the API (https://api.github.com/repos/dominik-fielmann/javascript-github-action/actions/workflows/test-action.yml/timing), I get the result:
{
    "billable": {
        "UBUNTU": {
            "total_ms": 63477
        }
    }
}

So that would be around one minute, right?

  • But when I look up the billable minutes spent on Github Actions in the current period in my account in the web, it says “6 minutes”.

Why does the API give me a different billable count than the web (or the usage report by XML)?
How can I calculate the number the web shows via the API?