# Discount line allocation

Split discounts across lines without breaking the booking.

Cortena can flag certain invoice lines as **line-level discounts** (for example a rebate on purchased goods). After the matching step, your tenant can choose how **booking account** and **VAT/BU** on those discount lines are set.

## Allocation modes

- **Guidelines only** · keep the suggestion from your chart of accounts and matching guidelines.
- **Mirror largest booking group** · copy codes from the donor line in the booking group with the **largest absolute total** per account (aggregate of non-discount lines sharing the same booking account).
- **Mirror line with largest absolute amount** · copy codes from the **single non-discount line** with the largest absolute line total.

## Where to configure

Open **Tenant Settings** and go to **Accounting preferences**. Under **Discount line allocation**, pick the mode that fits your process.

You can open accounting settings directly in the app: [Accounting settings](https://app.cortena.ai/?settings=accounting).

![Discount line allocation in accounting preferences](https://help.cortena.ai/assets/img/help/discount-line-allocation/02-discount-preferences.png)

Changing the preference applies to **new** processing immediately. **Existing invoices** keep their saved match until you **reprocess** them.

## What you see on an invoice

On the invoice workspace, discount lines are highlighted. When a policy override was applied at match time, the **booking** and **VAT/BU** tooltips show:

- A short explanation of the **tenant discount-line allocation** (which donor line was used).
- The **original matching** text underneath for audit, so you can still read what was suggested before the policy ran.

![Discount line tooltip showing allocation override](https://help.cortena.ai/assets/img/help/discount-line-allocation/01-discount-line-tooltip.png)

Updating accounting preferences requires the same access as other accounting connection settings in your tenant.