.NET 4.x Запись значений из цикла в Excel - Visual Basic .NET

Imports System.IO
Imports Microsoft.Office.Interop.Excel
Public Class Form1
    Dim a, b, c, p, Y, V
    Dim dt, t0 As Integer
    Dim ExApp As New Application           'Приложение Excel  
    Dim ExWB As Workbook                   'Книга Excel  
    Dim ExWS As Worksheet                  'Лист книги Excel 
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
    End Sub
    Private Sub Form1_FormClosing(sender As Object, e As FormClosingEventArgs) Handles MyBase.FormClosing
        ExApp.DisplayAlerts = False
        If ExWS IsNot Nothing Then ExWS = Nothing
        If ExWB IsNot Nothing Then ExWB = Nothing
        ExApp.Quit()
    End Sub
Private Sub ComboBox1_SelectedIndexChanged(sender As Object, e As EventArgs) Handles ComboBox1.SelectedIndexChanged
        If ComboBox1.Text = "1" Then p = 10
        If ComboBox1.Text = "2" Then p = 20
    End Sub
    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        If FolderBrowserDialog1.ShowDialog = DialogResult.OK Then
            TextBox3.Text = FolderBrowserDialog1.SelectedPath
        End If
        ExApp = CreateObject("Excel.Application")
        ExApp.Workbooks.Add()
        ExApp.ActiveWorkbook.SaveAs(Path.Combine(TextBox3.Text) & "" & "test.xls")
        ExApp.Visible = False
        ExApp.Sheets(1).Range("A1").Value = "k1"
        ExApp.Sheets(1).Range("B1").Value = "k2"
    End Sub
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
        a = TextBox1.Text
        b = TextBox2.Text
        t0 = TextBox4.Text
        If TextBox1.Text = String.Empty Then a = 0
        If TextBox2.Text = String.Empty Then b = 0
        If TextBox3.Text = String.Empty Then MsgBox("Не выбран путь сохранения!!!", , "ВНИМАНИЕ!")
       
        If ComboBox2.Text = "F" Then
            c = 2 * a * b
        End If
        If ComboBox2.Text = "F1" Then
            c = 5 * a * b
        End If
 
        Y = 8.5 / c
 
        Static counter = 0

        For counter = 0 To t0 Step 20
            If ComboBox1.Text = "1" And ComboBox3.Text = "s" Then
                V = 1 / Y
            End If
            If ComboBox1.Text = "1" And ComboBox3.Text = "s1" Then
                V = 1 / (Y ^ 2)
            End If
            If ComboBox1.Text = "2" And ComboBox3.Text = "s" Then
                V = 2 / Y
            End If
            If ComboBox1.Text = "2" And ComboBox3.Text = "s1" Then
                V = 2 / (Y ^ 2)
            End If
            If ComboBox2.Text = "F" Then
                a = V*p / 3
                c = 2 * a * b
            End If
            If ComboBox2.Text = "F1" Then
                a = V*p / 6.8
                c = 5 * a * b
            End If
            Y = 8.5 / c
        Next counter
            ExApp.Sheets(1).Range("A2:A" & counter).Value = V
            ExApp.Sheets(1).Range("B2:B" & counter).Value = Y
        ExApp.Save()
    End Sub
End Class