Macro to Count Duplicate Values

I am using the conditional formatting to highlight duplicate values. Then I want to check for all the highlighted cells and count the duplicates (dividing by 2). The conditional formatting records the interior color used to highlight is 13551615, but it doesn't recognize that the highlighted cells are this color later.

To highlight duplicates

Selection.FormatConditions.AddUniqueValues
    Selection.FormatConditions(Selection.FormatConditions.Count).SetFirstPriority
    Selection.FormatConditions(1).DupeUnique = xlDuplicate
    With Selection.FormatConditions(1).Font
        .Color = -16383844
        .TintAndShade = 0
    End With
    With Selection.FormatConditions(1).Interior
        .PatternColorIndex = xlAutomatic
        .Color = 13551615
        .TintAndShade = 0
    End With

To count highlighted cells

Sub Dup_Check2()

Dim RowsEnd As Integer
RowsEnd = Range("A" & Rows.Count).End(xlUp).Row

For i = 1 To RowsEnd
If Cells(i, 1).Interior.Color = 13551615 Then
Duplicate_Count = Duplicate_Count + 1
End If

Next

End Sub