Add a discount line after the subtotal in the report

Users have expressed a need to be able to add a specific line item to apply a discount (for example, a 10% discount) or a down payment directly after the subtotal when generating reports. Currently, it is not possible to do this natively without using workarounds. This improvement would result in a much more professional and transparent presentation for end customers. The development team has confirmed that this is a frequently requested feature and that it is planned for future updates.