Creating a custom column that calculates the previous row value by previous hour, date, & store

hi, Anonymous 

    s = your_table,
    f = (tbl as table) =>
        [rows = List.Buffer(Table.ToRecords(tbl)),
        rt = List.Generate(
            () => [i = 0, r = rows{0}, rr = Record.Field(r, "Total Consumed (w/o Cancellations)")],
            (x) => rows{x[i]}? <> null, 
            (x) => 
                [i = x[i] + 1,
                r = rows{i},
                rr =  List.Max(
                    {0, 
                    Record.Field(r, "Total Consumed (w/o Cancellations)") - 
                    Record.Field(x[r], "Total Consumed (w/o Cancellations)")})],
            (x) => x[r] & [Orders Dropped by Hour = x[rr]]
        ),
        z = Table.FromRecords(rt)][z],
    g = Table.Group(s, {"Store", "Date"}, {{"t", each f(Table.Sort(_, "Order Create Hour (UTC)"))}}),
    fin = Table.Combine(g[t])