IDENTIFY THE MOMENT OF VALUE CHANGE

Hi FieldsG,

Result:

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WMjAwNzQwNDAwMjAyMjMAAiUdJUsqYUND3ERsLAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"Long OP" = _t, #"2022-01" = _t, #"2022-02" = _t, #"2022-03" = _t, #"2022-04" = _t, #"2022-05" = _t, #"2022-06" = _t, #"2022-07" = _t, #"2022-08" = _t, #"2022-09" = _t, #"2022-10" = _t, #"2022-11" = _t, #"2022-12" = _t, #"2023-01" = _t, #"2023-02" = _t, #"2023-03" = _t, #"2023-04" = _t, #"2023-05" = _t, #"2023-06" = _t, #"2023-07" = _t, #"2023-08" = _t, #"2023-09" = _t, #"2023-10" = _t, #"2023-11" = _t, #"2023-12" = _t]),
    UnpivotedOtherColumns = Table.UnpivotOtherColumns(Source, {"Long OP"}, "Year Month", "Value"),
    AddedIndex = Table.AddIndexColumn(UnpivotedOtherColumns, "Index", 0, 1, Int64.Type),
    Ad_MomentOfChange = Table.AddColumn(AddedIndex, "Moment of Change", each try if [Value] = AddedIndex{[Index]-1}[Value] then null else [Year Month] otherwise null, type text),
    #"Added Custom" = Table.AddColumn(Ad_MomentOfChange, "Last Value Before Change", each if [Moment of Change] = null then null else Ad_MomentOfChange{[Index]-1}[Value], type text),
    #"Removed Columns" = Table.RemoveColumns(#"Added Custom",{"Index"}),
    #"Pivoted Column" = Table.Pivot(#"Removed Columns", List.Distinct(#"Removed Columns"[#"Year Month"]), "Year Month", "Value"),
    #"Filled Up" = Table.FillDown(#"Pivoted Column", Table.ColumnNames(#"Pivoted Column")),
    #"Filtered Rows" = Table.SelectRows(#"Filled Up", each ([Moment of Change] = "2023-07"))
in
    #"Filtered Rows"