Re: [WebERP-developers] inventory costing

[Phil D. <we...@pa...>]

> >
> > The purchase price in this field is not updated ... I don't think - I may
> > be corrected on this point - at the time of the closing of a shipment -
> > shipments of course cost in major freight and other costs into the items
> > that came in on the shipment.
> >
> >> I guess the primary things I can see missing from that table is the
> >> ability to track a quantity sold from the move record and possibly a
> >> column to track when the record is entirely sold to be used to narrow
> >> the result when looking for a cost.
> >


Well the stock value really doesn't change with a stock transfer?

Are you thinking of an Average cost type arrangement where the cost and 
quantity are maintained and on average a unit is worth the total of the cost 
divided by the total of the quantity on hand according to this table - I 
think this is how MYOB works.

> > Well that's not necessary for a FIFO valuation since one assumes that the
> > first stock in is the first stock out. One only requires to look at the
> > last receipts of stock that total the current balance of stock.
>
> Can you explain your thinking a bit more here?  I think you are saying
> to take the qoh for a current stock item and query back into your
> receipts to match up the last X receipts that make up that qoh and take
> the cost of the oldest matching receipt?
>

No accumulate the costs of the receipts in order of the most recently received 
stock to the point where the quantity accumulated matches the quantity on 
hand.

> That might be a more dynamic way to track the cost as opposed to
> updating discrete records at the time that stock is relieved.  I'm not
> sure if one way is preferable over another.  Having discrete records
> might be preferable for updating inventory cost records.
>
> Something else I thought of this morning is that there is a record in
> the stockmoves table for both incoming and outgoing stock.  I am only
> concerned with incoming movements for cost calculations so there needs
> to be some way to differentiate the record types in that table.  

Indeed there is - checkout the systypes table typeid=25 is stock receipts - 
there is a foreign key to stockmoves



> And 
> that also started me thinking whether it would be better to add a new
> table instead of trying to piggy back on the existing table?  I will
> defer to you on that.
>

Personally I am a big fan of standard costing because:

1. Costs change on every shipment and it is not always appropriate to change 
the cost for decision making based on an airfreight shipment or based on a 40 
footer. The true cost for making logical decisions is the based somewhere in 
the middle - bearing in mind proper order sizes.

2. I like to see the differences reported against the standard cost so we can 
see :
	(i) if the business is shipping economically
	(ii) the effect of exchange rate factors
	(iii) the effect of supplier price changes

3. It allows very speedy - same day reporting

You should read up a bit on it - there is some info in the manual as to how it 
works

-- 
Phil Daintree
webERP Project Admin