ARFoundation1.5 check Android supports ARCore

I want to check if Android supports ARCore.
Discrimination was implemented using the CheckAvailability method of the ARSession class.
I want to receive [Unsupported] status on devices that do not support ARCore, but I receive [NeedsInstall] status.
This may be because the result of isSupport () is true in the CheckAvailability method.
Why is CheckSupport () result true with the CheckAvailability method?

Unity2018.3.1f1
ARFoundation1.5.0-preview6
ARCore XR Plugin 2.1.2

Android
XperiaSVO33 Android 8.0 (ARCore not supported)
AQUOS scene SH-01K Android 8.0 (ARCore not supported)

    private void OnEnable ()

    {



        StartCoroutine (DeviceChack ());

    }



    IEnumerator DeviceChack ()

    {

        if (ARSession.state == ARSessionState.None ||

            ARSession.state == ARSessionState.CheckingAvailability)

        {

            yield return ARSession.CheckAvailability ();

        }



        // check States

        Debug.Log (ARSession.state);



    }