Find last changed value and the date of change using Power Query

Hello, omarelmb123 

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("dc9BDoAgEAPAv3A2aXcXUf7gDwz//4ZgRCJZLz1MemjPM0hYwtGCGUIo1UJZHtcaqhCZ3JrnHydEh2v3WqZMHpsrOPdvN9A8j2D0fAXX4dZ/SQKT5xu4eb5/dg7Pvte/r5cL", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [ID = _t, Level = _t, Date = _t]),
    recs = Table.ToRecords(Source),
    count = List.Count(recs),
    gen = 
        List.Generate(
            () => [i = 0, r = recs{0} & [Last changed value = null] & [Last Changed Date = null]],
            (x) => x[i] < count,
            (x) => 
                [i = x[i] + 1, 
                r = recs{i} & 
                    (if recs{i}[ID] <> x[r][ID] 
                    then [Last changed value = null] & [Last Changed Date = null]
                    else if recs{i}[Level] <> x[r][Level] 
                            then [Last changed value = x[r][Level]] & [Last Changed Date = recs{i}[Date]]
                            else [Last changed value = x[r][Last changed value]] & [Last Changed Date = x[r][Last Changed Date]])
                ],
            (x) => x[r]
        ),
    z = Table.FromRecords(gen)
in
    z