Ignore text marked as No Proofing language

Question

I have a word document with some text marked as Review/Language/Do not check spelling or grammar. Why is my code not considering "Proofing"?

Sub SentenceProofing()
    Dim iWords As Integer
    Dim Text As String
    Dim oRange As range

    Set oRange = ActiveDocument.range

    If Not ActiveDocument.Saved Then
        ActiveDocument.Save
    End If

    'Set number of words
    iWords = 15

    With oRange.Find
         .NoProofing = False
         For Each MySent In oRange.Sentences
            If MySent.Words.Count > iWords Then
               ActiveDocument.Comments.Add _
               range:=MySent, Text:="Sentence longer than 15 words"
            End If
         Next
    End With
End Sub