Почему округляет?

Public Class Form1
    Dim a As Char
    Dim FP As Double
    Public Sub TextBox1_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox1.KeyPress
        a = e.KeyChar
        If Char.IsDigit(a) Or Char.IsPunctuation(a) Then
            If Char.IsPunctuation(a) Then
                If sender.text.contains(",") Then
                    e.Handled = True
                Else
                    e.KeyChar = Chr(44)
                End If
            End If
        ElseIf Asc(a) = 8 Then
        Else
            e.Handled = True
        End If
        FP = Val(TextBox1.Text)
    End Sub
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        TextBox2.Text = FP
    End Sub
End Class

Public Sub TextBox4_LostFocus(ByVal sender As Object, ByVal e As System.EventArgs) Handles TextBox4.LostFocus
        TextBox4.Text = TextBox4.Text.Replace(".", ",")
        If IsNumeric(TextBox4.Text) = True And TextBox4.Text <> "" Then
            Valuta = TextBox4.Text
            TextBox4.Text = String.Format("{0:c}", Valuta)
        End If
        COB = Val(Valuta)
    End Sub

Dim a As Char
Dim FP, CSD, COB, CPI As Double
Public Sub TextBox2_KeyPress(ByVal sender As Object, ByVal e As System.Windows.Forms.KeyPressEventArgs) Handles TextBox2.KeyPress
        a = e.KeyChar
        If Char.IsDigit(a) Or Char.IsPunctuation(a) Then
            If Char.IsPunctuation(a) Then
                If sender.text.contains(",") Then
                    e.Handled = True
                Else
                    e.KeyChar = Chr(44)
                End If
            End If
        ElseIf Asc(a) = 8 Then
        Else
            e.Handled = True
        End If
End Sub
Public Sub РассчитатьToolStripMenuItem_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles РассчитатьToolStripMenuItem.Click
        FP = Val(TextBox2.Text)
CO = Math.Round(FP * (CSD + COB + CPI), 2)

Sub IsNum(ByVal text As String, ByVal ctl As Object)
        On Error Resume Next
        If IsNumeric(text) = False Then
            ctl.Text = text.Remove(text.Length - 1, 1)
            ctl.SelectionStart = ctl.Text.Length
            ctl.SelectionLength = 0
        End If
    End Sub

Private Sub TextBox1_TextChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles TextBox1.TextChanged
        IsNum(sender.Text, sender)
    End Sub