Added by System means that the stock has been added automatically when the goods have been added to the sales order, in the instance where the stock code is under the status Consumable.
Consumable Product - This is a product where it will never go for purchasing as with all other products, so when sold if there is none in stock the system will automatically add double the quantity required to allow the requirement to be automatically allocated. Depending on the type of product, dealers may need to keep an eye on this so that they do not keep the product live when no stock exists. This is mostly for shop environments whereby for example they sell pens in assorted colours and rather than have several different codes for each colour, just lump them as one product at one price(normally this would also be a till favourite as well).**
For more information on product status' click here.