ZXing Barcode Scanner , not returning FNC1 character for DataMatrix in Xamarin

Question

I have been using ZXing .Net for scan DataMatrix (standard GS1) with Xamarin with following options. But still not getting ASCII value (FNC1).

private async void scanButton_Clicked(object sender, EventArgs e)
    {

        var options = new ZXing.Mobile.MobileBarcodeScanningOptions
        {
            PossibleFormats = new List<ZXing.BarcodeFormat>() {                   
                ZXing.BarcodeFormat.DATA_MATRIX
            }
        };
        options.AssumeGS1 = true;
        //Scanning part
        var barcode  = "";
        scanPage = new ZXingScannerPage(options);

        scanPage.OnScanResult += (result) =>
        {
            scanPage.IsScanning = false;

            Device.BeginInvokeOnMainThread(() =>
            {
                Navigation.PopAsync();
                barcode = result.Text;
            });
        };

        await Navigation.PushAsync(scanPage);
    }

Why i can't see ASCII value (FNC1) ?

Thanks