OK, I tried

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Code:
Sub LineSpacing6pt()
Dim opara As Paragraph
Dim i As Long
For i = 1 To Selection.Range.Paragraphs.Count
Set opara = Selection.Range.Paragraphs(i)
opara.Range.Style.NoSpaceBetweenParagraphsOfSameStyle = False
opara.Range.ParagraphFormat.SpaceAfter = 6
Next i
lbl_Exit:
Exit Sub
End Sub