Calculate not accumulated amounts from accumulated data structure

Hi marcofalzone01 ,

Based on the attached file, keep the first two steps (i.e. delete everything from the pivot step).

Then, add a custom column and add code below:

[Accumulated Amount] - 
List.Sum(
    List.InsertRange(
        Table.SelectRows(
            #"Changed Type", 
            (x)=> 
            x[Periods or Index Field]
             = [Periods or Index Field] - 1 
             and 
             x[Other Category]
             = [Other Category]
        )[Accumulated Amount]
    ,0,{0}
    )
)

You should get the result below:

The code contains two criteria: Other Category and Index.

Regards

KT