Code:
Sub addCols()
    Dim ws As Worksheet
    Dim j As Long
    Dim lr As Long
    
    Set ws = ActiveSheet
    lr = ws.Range("a4").End(xlDown).Row 'in your example, row 15
    
    With ws
        .Range("b1").Copy
        .Range("g1").PasteSpecial
        .Range("g2:j2").PasteSpecial
        .Application.CutCopyMode = False
        .Range("g1").Select
        
        .Range("g1").Value = "Forecast"
        .Range("g1:j1").MergeCells = True
        .Range("g1:j1").HorizontalAlignment = xlCenterAcrossSelection
        
        
        .Range("g2").Value = "Best"
        .Range("h2").Value = "Likely"
        .Range("i2").Value = "Worst"
        .Range("j2").Value = "Spread"
        
        
        
        .Range("b5:b" & lr).Copy
        .Range("g5").PasteSpecial xlPasteFormats
        .Range("h5").PasteSpecial xlPasteFormats
        .Range("i5").PasteSpecial xlPasteFormats
        .Range("j5").PasteSpecial xlPasteFormats
        
        .Range("g2:g" & lr).Interior.Color = 12379352
        .Range("h2:h" & lr).Interior.Color = 15986394
        .Range("i2:i" & lr).Interior.Color = 14281213
        .Range("j5").Formula = "=g5-i5"
        .Range("j5").Copy
        .Range("j6:j" & lr).PasteSpecial
        Application.CutCopyMode = False
        
        .Range("b" & lr + 2).FormulaR1C1 = "=SUM(R[" & 5 - (lr + 2) & "]C:R[-2]C)"
        .Range("b" & lr + 2).Copy
        .Range("c" & lr + 2 & ":e" & lr + 2).PasteSpecial
        .Range("g" & lr + 2 & ":j" & lr + 2).PasteSpecial
        Application.CutCopyMode = False
        .Range("a" & lr + 2).Value = "Total"    'changed this to "lr +2"
        
        .Range("k1").Value = "Comments"
        .Range("k1").Font.Bold = True
        .Range("k1").Font.Italic = True
        .Range("k1").ColumnWidth = 20
        .Range("k1").HorizontalAlignment = xlCenter
        .Range("k1:k2").Merge
        .Range("g5").Select
        
        
        .Range("g1:j1").BorderAround xlContinuous, xlThin, xlColorIndexAutomatic
        .Range("g2:i2").BorderAround xlContinuous, xlThin, xlColorIndexAutomatic
        .Range("j2").BorderAround xlContinuous, xlThin, xlColorIndexAutomatic
        .Range("k1:k2").BorderAround xlContinuous, xlThin, xlColorIndexAutomatic
        With .Range("g3:g" & lr).Borders(xlEdgeLeft)
            .LineStyle = xlContinuous
            .Weight = xlThin
            .ColorIndex = xlColorIndexAutomatic
        End With
        With .Range("i3:i" & lr).Borders(xlEdgeRight)
            .LineStyle = xlContinuous
            .Weight = xlThin
            .ColorIndex = xlColorIndexAutomatic
        End With
        With .Range("j3:j" & lr).Borders(xlEdgeRight)
            .LineStyle = xlContinuous
            .Weight = xlThin
            .ColorIndex = xlColorIndexAutomatic
        End With
        With .Range("k3:k" & lr).Borders(xlEdgeRight)
            .LineStyle = xlContinuous
            .Weight = xlThin
            .ColorIndex = xlColorIndexAutomatic
        End With
    End With
    
    Set ws = Nothing
End Sub