Cannot change http_checks interval

I deployed an app with this config in fly.toml (Below is a part of the file).

    grace_period = "60s"
    interval = "5m"
    method = "get"
    path = "/health"
    protocol = "http"
    restart_limit = 0
    timeout = "5s"

And my config is OK when run fly config validate.

But, fly config display returns

            "http_checks": [
                    "grace_period": "10s",
                    "interval": "1m",
                    "method": "get",
                    "path": "/health",
                    "protocol": "http",
                    "restart_limit": 0,
                    "timeout": "5s",
                    "tls_skip_verify": false

I set interval to 5m in toml, but it seems 1m is set on server.
I deployed several times but interval was not changed.
How can I set interval to a value other than 1m?