Adding new rows at specific locations

• Group by Product
• In the Aggregation, create a Record that has the appropriate zero level entries
• Prepend this record to the orginal records making up the sub-table

let
    Source = Excel.CurrentWorkbook(){[Name="Table13"]}[Content],
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Product", type text}, {"Level", Int64.Type}, {"Component", type text}}),

    #"Grouped Rows" = Table.Group(#"Changed Type", {"Product"}, {
        {"Add Row", (t)=> 
            {Record.FromList({t[Product]{0},0,t[Product]{0}},{"Product","Level","Component"})} & 
            Table.ToRecords(t)}
        }),

    #"Removed Columns" = Table.RemoveColumns(#"Grouped Rows",{"Product"}),

    #"Expanded Add Row" = Table.ExpandListColumn(#"Removed Columns", "Add Row"),
    #"Expanded Add Row1" = Table.ExpandRecordColumn(#"Expanded Add Row", "Add Row", {"Product", "Level", "Component"})
in
    #"Expanded Add Row1"