Production order

I tried to enter data into production order I have already enter opening stock for waste generated during production last month. When producing this month I tried to enter waste incurred but going to inventory item instead of adding the new waste to opening stock it deducted the new waste from opening stock. Pls. Help me our

the waste is a finished product and not a consumed good in producing the finished good.
if you add the waste as a material used for production of goods, then it will reduce from inventory.
Manager at present is not capable of recording a production order where more than one finished goods are produced from a raw material. i think you had already been informed about this earlier by @Tut here.