unusual unpivot for multiple columns

Hi vissvess 

We can do the unpivot after some tranformations

Please see attached file for steps. I added another dummy row for testing

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjc2MzFR0lEqSikuAdHJiUUl+XkKSfkVQE5lRkq6MZB2Li3OyASKGgLZiSkmaRlAOri0oCC/qEShOCc1tSxVKVYHYpYp1CxTFLMOLQBBI6iRJkhGgsSqSpMygZRffh66obEA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type text) meta [Serialized.Text = true]) in type table [SaleID = _t, Part1 = _t, Part1Desc = _t, Part2 = _t, Part2Desc = _t, Part3 = _t, Part3Desc = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"SaleID", Int64.Type}, {"Part1", type text}, {"Part1Desc", type text}, {"Part2", type text}, {"Part2Desc", type text}, {"Part3", type text}, {"Part3Desc", type text}}),
    #"Unpivoted Columns" = Table.UnpivotOtherColumns(#"Changed Type", {"SaleID"}, "Attribute", "Value"),
    #"Added Custom" = Table.AddColumn(#"Unpivoted Columns", "Custom", each Text.Range([Attribute],4,1)),
    #"Added Custom1" = Table.AddColumn(#"Added Custom", "Custom.1", each Text.Replace([Attribute],[Custom],"")),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom1",{"Attribute"}),
    #"Pivoted Column" = Table.Pivot(#"Removed Columns", List.Distinct(#"Removed Columns"[Custom.1]), "Custom.1", "Value"),
    #"Removed Columns1" = Table.RemoveColumns(#"Pivoted Column",{"Custom"})
in
    #"Removed Columns1"