Addition of a down payment feature (deposit) deducted after taxes and fees

Several users have requested the ability to add a down payment or deposit that is automatically subtracted from the total quote amount—that is, after fees and taxes have been applied. Currently, the workaround involves entering the deposit as a task with a negative quantity calculated before taxes and without fees, which is complex and not very intuitive. This new feature would clearly display the remaining balance due directly on the quote, thereby eliminating the need for manual calculations or the requirement to immediately use invoicing software.