Stock information with Quote and Sales Order

Stock information with Quote and Sales Order

When creating a new quote the stock information is correctly update (the quantity reported in the Quote is set as "Qty in demand").
From this point on the Quantity in demand cannot be decreased by changing the status of the Quote or creating a Sales Order related to the Quote.
For example even setting the Quote in "Closed Lost" the "Qty in demand" field doesn't decrease.
The same happens with Sales Order: creating a new Sales Order the "Qty in demand" is increased (except that, correctly, if the Sales Order is made starting from a Quote).
Even setting the Sales Order as "delivered" the quantity is always set as "Qty in demand" and the "Qty in stock" is not decreased.
I tried do this with different quotes and sales order (either from Ajax edit or from the Edit page).

Thanks for your help,
Andrea Rocca
Andrea Rocca