Change Cumulative Sums back to differences

Hi, ShamR9T 

there was some miss calculations in the previous solution. 

the solution is okay now. 

There is some workaround in this query that you need to modify. 

Here is the PQ code

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WCk7MSS1WCEgtKs7PU9JR8slPTizJBDM9S1JzgZShrldinq6RMZBpgWAamiLYRkYwdqxOtJIjSBaIo6A0CBuBMUjWCcqLAGIDKDaEyzoDWSATI1FkQGIwk42hekEypkBsDsbIJkcimQzBMJNhrkKTjQUA", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [#"(blank)" = _t, #"(blank).1" = _t, #"(blank).2" = _t, #"(blank).3" = _t, #"(blank).4" = _t, #"(blank).5" = _t, #"(blank).6" = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"(blank)", type text}, {"(blank).1", type text}, {"(blank).2", type text}, {"(blank).3", type text}, {"(blank).4", type text}, {"(blank).5", type text}, {"(blank).6", type text}}),
    #"Promoted Headers" = Table.PromoteHeaders(#"Changed Type", [PromoteAllScalars=true]),
    #"Changed Type1" = Table.TransformColumnTypes(#"Promoted Headers",{{"Sales Person", type text}, {"Location", Int64.Type}, {"Item", type text}, {"1-Jan-23", Int64.Type}, {"8-Jan-23", Int64.Type}, {"15-Jan-23", Int64.Type}, {"22-Jan-23", Int64.Type}}),
   // Step 2: Unpivot the date columns
    UnpivotedColumns = Table.UnpivotOtherColumns(#"Changed Type1", {"Sales Person", "Location", "Item"}, "Date", "Value"),

   // Step 3: Group by Sales Person, Location, Item, and Date
    GroupedTable = Table.Group(UnpivotedColumns, {"Sales Person", "Location", "Item", "Date"}, {{"Cumulative Sum", each List.Max([Value]), type number}}),
    AddIndex = Table.AddIndexColumn(GroupedTable, "Index", 0, 1, Int64.Type),

     AddPreviousDaySales = Table.AddColumn(AddIndex, "Previous Day Sales", each if [Index] > 0 then AddIndex{[Index]-1}[Cumulative Sum] else 0),
    AddSalesEachDay = Table.AddColumn(AddPreviousDaySales, "Sales Each Day", each [Cumulative Sum] - [Previous Day Sales]),
    
    // Step 4: Remove unnecessary columns
    RemovedColumns = Table.RemoveColumns(AddSalesEachDay,{"Index", "Previous Day Sales"})
in
    RemovedColumns

try to understand the values that is showing minus, the calculation is alright with the given logic. You wan to subtract values with the previous values. You need to adjust it a little bit. But this should be very helpful.