account_invoice_fixed_discount

Purpose

Allows invoicing users to apply fixed-amount discounts on invoice lines and have them reflected in accounting computations and reports.

Features

account.move.line: Adds a fixed-amount discount field on invoice lines that multiplies by the line quantity.
account.move.line: Recomputes invoice line totals using the fixed discount before taxes to keep amounts accurate.
account.move.line: Synchronizes the fixed discount and percentage fields during on-change events.
account.tax: Injects the percentage derived from the fixed discount into tax calculations so taxes respect the rebate.
account.move: Exposes the fixed discount column in invoice line forms for users with the dedicated group.
security: Creates a Fixed Discount group automatically implied by the standard invoicing group.
reports: Displays both the fixed discount amount and the percentage on the printed invoice when such discounts exist.