OpenERP FIFO Method implementation

Always searching about FIFO stock costing method for Malaysia OpenERP localization , and the method that is now in Proof of concept is :

1. Add Amount and FIFO_Qty_Balance, unit price fields in Stock transaction table.
2. When it is a Purchase/Incoming receive, it will
     record the FIFO_Qty_Balance , unit price and then Amount  = unit price x FIFO_Qty_Balance
3. When it is a Sales/Delivery , it will
    record the FIFO_QTY_Balance as Zero(0) , unit price as Zero(0) and then calculate
    Amount = loop all the receive in (2) with FIFO_Qty_Balance greater than zero
                    and deduct the receive FIFO_QTY_Balance with the qty issued for Sales/Delivery.
                    and count the accumulated Amount by unit price x FIFO_QTY_Balance issue
                           from the  Purchase/Incoming receive transaction(s).

This will give the stock transaction amount field for
1. Purchase/Incoming to show the unit price purchased as well as the purchase cost for the item.
2. Sales/Delivery to show the amount which is the FIFO cost from the stock transaction.

at this moment , what we are thinking to do to temporary solve our concerns is to produce
reports from the above stock transaction file and then get the accountant to enter this stock
values into the journal . (Emm... doesn't sound very interested , :) )

there are still two concerns that i have not settled or looking for a good idea ...
1. Post the calculated FIFO cost  to account.
2. Recalculate FIFO cost process if Incoming and Delivery date is been modified 

Do you have any comments and feel free to share your idea or the best way you think can
design an effective FIFO costing method in Malaysia OpenERP localization ?

Or perhaps you have even a better idea to share ? After we settle the two concerns ,we will release
the code , so do join the members of the blog and be the first to get to know when we release
the code , or if you need some help , call us or meet up with us , we are very nice people , :>

Cheers and happy openERPing !