Sub AddValues()
Dim arrIn, arrP, lngI As Long, bytB As Byte
arrIn = Range("A1").CurrentRegion.Value
For lngI = 1 To UBound(arrIn, 1)
arrP = Split(arrIn(lngI, 1), ",")
For bytB = 1 To 3
arrIn(lngI, 1) = arrIn(lngI, 1) & "," & arrP(UBound(arrP))
Next bytB
Next lngI
Range("D1").Resize(UBound(arrIn, 1), 1) = arrIn
End Sub