How to reschedule EDD based on production capacity - Power Query

For offset, it is not working or weird result. All assigned EDD for that product should not exceed more than October 2025, it should arround october 15 to 20.

Please extend the duration of calendar current date + 90 days, in the calendar table M code.

Here I am attaching all the rows of the orginal table and exact product type capacity. Also, for performance I only consider the non null EDD. changed your code a little. Yearly holiday table, already merged with the calendartable. so you do not need to use yearly holiday table.

let
    // fx to find position of working day in the list
    wd_position = (d as date) => List.PositionOf(working_days, d, Occurrence.First),
    // list of working days
    working_days = List.Buffer(
        List.Sort(
                Table.SelectRows(CalendarTable, (x) => x[Is Working Day] = "True")[Date]
        )
    ),
    // capacity by product type
    caps = Function.Invoke(Record.FromList, List.Reverse(Table.ToColumns(Capacity))),

    // Spliting Tables
    selectedColumns = {"Date", "Order Code", "Customer", "Product Type", "CS Approved Date", "Order Qty", "Estimated Delivery Date", "EDD"},
    orderDetails_Selected = Table.SelectColumns(OrderDetails, selectedColumns),

    // Creating 2 Tables With. One with null and other with non null
    OrderDetailsWithNullEDD = Table.SelectRows(orderDetails_Selected, each [EDD] = null),

    // With non null EDD
    OrderDetailsWithNonNullEDD = Table.SelectRows(orderDetails_Selected, each [EDD] <> null),

    // Tables with the remaining columns
    remainingColumns = List.Difference(Table.ColumnNames(OrderDetails), selectedColumns),
    orderDetails_Remaining = Table.SelectColumns(OrderDetails, remainingColumns),


    // orders sorted by prod type and estimated DD
    sorted = Table.Sort(OrderDetailsWithNonNullEDD, {"Product Type", "EDD", "CS Approved Date"}),
    // and >> to list
    orders = List.Buffer(Table.ToList(sorted, (x) => x)),
    // go over the list
    processing = List.Generate(
        () => [
            i = 0,
            prod = orders{0}{3},
            iw = wd_position(orders{0}{7}),
            cap = Record.Field(caps, prod),
            flag = orders{0}{5} > cap,
            current_qty = if flag then 0 else orders{0}{5},
            cap_usage = current_qty
            //delivery_date = orders{0}{7}
        ],
        (x) => x[i] < List.Count(orders),
        (x) => [
            i = x[i] + 1,
            prod = orders{i}{3}, // current order's product type
            same_prod = x[prod] = prod, // check if prod type is the same as last order 
            cap = if same_prod then x[cap] else Record.Field(caps, prod), // current capacity
            flag = orders{i}{5} > cap, // check if qty is greater than cap
            current_qty = if flag then 0 else orders{i}{5}, // this order usage quantity
            cap_is_full = (not same_prod) or 
                (x[cap_usage] + current_qty) > cap or
                working_days{x[iw]}? is null or
                orders{i}{7} > working_days{x[iw]}, // reset capacity??
            cap_usage = if cap_is_full then current_qty else x[cap_usage] + current_qty, // capacity used
            iw = if (not same_prod) then wd_position(orders{i}{7}) // position in working days calendar
                else if cap_is_full  
                    then x[iw] + 1 
                    else x[iw]
        ],
        (x) => orders{x[i]} & (if working_days{x[iw]}? is null 
            then {null, null, null, "calendar is full"}
            else {x[cap], x[cap_usage], working_days{x[iw]}, if x[flag] then "order out of capacity" else null}
        )
    ),
    result = Table.FromList(processing, (x) => x, Table.ColumnNames(sorted) & {"capacity", "usage", "assigned_EDD", "flag"}),
    #"Changed Type" = Table.TransformColumnTypes(result,{{"Order Qty", Int64.Type}, {"assigned_EDD", type date}})
in
    #"Changed Type"

Here is the updated capacity table:

Product Type                    Capacity

for each day, offset should maintain showing orders total sum less than 600,000. other product will follow the same. Any whole order unable to fit that date, spill over to the next date, which must be working date. when spilling consider the spill orders + where you spilling, consider those order also, to check capacity logic.

Any whole order value > capacity, leave it as it is. Also, same for Urgent, Urgent (Revised), Urgent (Additional) in the cs comment column, just leave it as it is. 

Hope this info helps. Kindly check attached file here.