xlookup problem

Hello - this is how you can get the result expected with Power Query:

Table.AddColumn(#"Changed Type", "Custom", each Table.SelectRows(#"Changed Type", (x)=> x[Code compare]=[Code nr] ){0}[Value])

Thanks for posting the script.  You are getting additional rows when you expand the tables in the last step, is because the previous step, in which the new column is added, is returning a table in each row, and that table has more than one row. When you expand the column of tables, each row in the original table is expanded by the number of rows that are in the table in each F_origin.  You will need to either filter the rows in each F_origin prior to expanding, like this:

Table.TransformColumns ( 
    #"Personalizado Adicionado",
    {
        {
            "F_origin",
            (t) => Table.SelectRows ( t, each t[Column1] = "Your critieria here" )
         }
    }
)

Or drill down further when you add F_origin as a new column, like this:

Table.AddColumn(#"Preenchido para Baixo", "F_origin", each Table.AddColumn(#"Preenchido para Baixo", "Custom", each Table.SelectRows(#"Preenchido para Baixo", (x)=> x[Ord. Fabrico]=[#"Ord. Fabrico (Origem)"] ){0}[Formato][ColumnName]{RowIndexBase0}))