The rule for inventory deduction is that once a Sales Order is processed, the quantity of inventory should be decreased by the amount of sales order automatically
You have “Wallet” as a product and the total quantity of available wallets is 15. You processed a sales order of 5 wallets, so the inventory left for the products should be 10 and this is done automatically.
But, VTiger does not work like this. In VTiger the deduction in the inventory will only takes place once you generate the invoice.
Lets take a practical example to understand this process
A company has 20 wallets in stock
They processed a sales order of 5 wallets
But, Vtiger stills shows 20 wallets in inventory
To update the inventory, you will have to generate the invoice. Once, you generate the invoice the inventory available in the products will be reduces by the amount of quantity of sales order
After generating the invoices, the inventory will be decreased by the amount of sales order
So, whenever you process a sales order, to readjust the the product quantity automatically you have to generate the invoice