Comment 9 for bug 610738

Hello,

I am not sure it must be like that. As far as I remember my accounting books (at least for belgium) average costs must be changed only when you receive or produce products, not when you send the products. The rule is (Qty Rcvd * PO Price + Existing Qty * Current Cost) / (Qty Rcvd + Existing Qty).

The following operations should not change the average cost:
  - delivering a customer (with products that come from a particular supplier or not)
  - scrapping defects products (that come from a particular supplier or not)
  - returning the products back to a supplier (fortunately, otherwise you have to reconcile each product you send to a
    supplier with the right reception order.)

In FIFO or LIFO, those operations impact the average price, but I don't think it's the case in average cost. I looked on the web for information about this but I did not find any relevant one ? Do you have a link that explicitly says that sending product back to the supplier

If you really want your average cost not to be impacted by the products, here is two propositions of setup:
  - receive the order only partially (and cancel the remaining part)
  - set the input location as a supplier location instead of an internal one. (eventually a quality control location like the one in
    the demo data of the stock_location module.) this way, you can return the products back to your supplier before they are
    valorized in your accounting.

Our policy has been to keep OpenERP simple, if you need others features, it's better to do it as an extra module than adding several fields in several screens for each feature. One can have a lot of new requests around average cost:
   - impact the service/delivery costs automatically based on what's on the SO
   - impact the service/delivery costs automatically based on what's on the reception order
   - change the valorization of the avg cost if you scrap products from a supplier
   - propose the price which is on the supplier invoice and not on the purchase order (and thus reconcile both)
   - add automatically delivery invoices later on the cost of some products that can from a reception.
   - updating the average cost on manufacturing orders (which is the biggest lack of the current system in my opinion)

All those propositions are valid and some companies will need it. But I repeat our policy: "make it simple" ! If someone need more feature, we can still provide this as extra module so that the main modules remain simple.

PS/ I agree with Nicolas, the status is not "critical". A security issue or a bug that prevent using the software IS critical. A new feature should not be critical.

We still have hundreds of tasks to close for the V6. I hope your understand our point of view to not change the official addons for this in order to not add complexity, so I propose starting to work on a new module that implements what you need.