No, not at Wavelet EMP. When a negative quantity is entered into an invoice, no reference invoice/cashale is specified, this is a loop hole because
no checking of the return price is enforced to ensure the returning price is lower or equal to the selling price.
In addition, when there's a trade in of stock, it should affect the moving average stock values. By simply putting a negative quantity at the
invoice, it makes the calculations of the COST OF GOODS SOLD, the new average stock values to skew.
In order to ensure the integrity of accounting module, inventory module, and various sales return business logic, Wavelet EMP does not allow users to put negative quantity or price in the INVOICE/CASHSALE. Creating a proper sales return is the right step to do.