Removing Promotional Data From Sales

let
    // duration step
    one_day = #duration(1, 0, 0, 0),
    // function to generate list of dates and sales
    calc = (x, y, n) => 
        [daily_sales = (y{1} - x{1}) / n, 
        lst = List.Zip({List.Dates(x{0} + one_day, n - 1, one_day), List.Numbers(x{1} + daily_sales, n - 1, daily_sales)})][lst],
    // Source data - replac with yours
    Source = Excel.CurrentWorkbook(){[Name="Table1"]}[Content],
    tp = Table.TransformColumnTypes(Source,{{"Date", type date}}),
    // filter out promo sales and get list from table
    nopromo_table = Table.SelectRows(tp, (x) => x[Promo Flag] = 0),
    nopromo = List.Buffer(Table.ToList(nopromo_table, (x) => {x{0}, x{2}})),
    // generate list of missing dates and sales 
    generate = List.Generate(
        () => [i = 0, s = nopromo{0}, n = 0, res = {}],
        (x) => x[i] < List.Count(nopromo),
        (x) => 
            [
                i = x[i] + 1, 
                s = nopromo{i}, 
                n = Duration.Days(s{0} - x[s]{0}), 
                res = if n <= 1 then {} else calc(x[s], s, n)
            ],
        (x) => x[res]
    ), 
    // generated list >> to table
    baseline_sales = Table.FromList(List.Combine(generate), (x) => x, {"Date", "Sale Qty"}),
    // combine and sort new sales table, fill down product column
    all = Table.Sort(nopromo_table & baseline_sales, "Date"), 
    fd = Table.FillDown(all, {"Product"})
in
    fd