Help with calculations on button click

[barentinematt]

Not really sure what my problem is but here we go.
Ive created a simple windows form in visual studio to calculate an NPS (Net Promoter Score) average. Everything is finally working with one exception. When I click my calculate button only half of the calculations are done, I have to click it once more to get the code to finish. Im new to vb but it seems to me like the problem is the code is getting ahead of itself and since the end formula needs the results from several of my labels it cant finish. Im sure its a simple fix but I cant quit get it. Any assistance would be much appreciated.

Private Sub butCalculate_Click(sender As Object, e As EventArgs) Handles butCalculate.Click
        Dim detracter As Double
        Dim neutral As Double
        Dim promoter As Double
        Dim total As Double
        Dim TOTAL1 As Double

        detracter = Double.Parse(lblD.Text)
        neutral = Double.Parse(lblN.Text)
        promoter = Double.Parse(lblP.Text)

        lblD.Text = Val(lblD.Text) + txtDetractor.Text
           
        lblN.Text = Val(lblN.Text) + txtNeutrals.Text

        lblP.Text = Val(lblP.Text) + txtPromoters.Text

            TOTAL1 = (promoter - detracter) / (promoter + neutral + detracter)
            lblTotal.Text = TOTAL1.ToString("P")
            lblTotal.Visible = True
            lblTotal.Left = (Me.ClientSize.Width / 2) - (lblTotal.Width / 2)

            txtDetractor.Text = "0"
            txtNeutrals.Text = "0"
        txtPromoters.Text = "0"

        total = detracter + neutral + promoter
        lblT.Text = total.ToString()

    End Sub