> ## Documentation Index
> Fetch the complete documentation index at: https://docs.alvys.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Supplemental Invoicing

> Bill charge changes after the original invoice with supplemental invoices, including setup, numbering, settings precedence, and accounting sync.

Supplemental Invoicing lets you bill customers for charge changes after the original invoice has been generated. Alvys creates a separate supplemental invoice for the difference instead of changing the original invoice number.

## Overview

When **Invoice Update Mode** is set to **Supplemental**, Alvys issues additional invoices that contain only the delta — the amount added or removed since the last invoice on the load. The original invoice stays unchanged.

Supplemental invoices use letter suffixes on the load number (for example, `1001234-A`, `1001234-B`). Each supplemental is its own invoice record in Alvys and can be submitted, tracked, and paid independently.

Supplemental mode applies to **Individual** invoice type only. [Summary Invoicing](/en/help/accounting-settlements/how-to-use-summary-invoicing) supports Amendment mode only and does not support supplementals.

## Before You Start

You need the **Billing** permission to generate and submit invoices.

Set **Invoice Update Mode** to **Supplemental** before you generate the first invoice on a load. You can configure this at the subsidiary level or override it on the customer profile. See [Which settings apply?](#which-settings-apply) below.

## Which settings apply?

Alvys resolves invoicing settings for each load in this order:

1. **Customer profile** invoicing settings for the load's **Invoice As** subsidiary
2. **Subsidiary / Management** defaults when the customer has no override

<Warning>
  Customer-level settings take precedence over subsidiary defaults. If you change invoicing settings on the load or subsidiary but the customer profile has its own settings for that **Invoice As** subsidiary, the customer settings control supplemental behavior.
</Warning>

Load-level settings that were captured earlier do not override current customer or subsidiary settings. If you update invoicing settings and the load does not reflect the change, see [Invoicing settings not reflected on the load](/en/help/accounting-settlements/i-changed-the-invoicing-settings-but-it-s-not-reflected-on-the-load).

<Tip>
  To confirm which settings apply, open the customer profile, scroll to **Invoicing Settings**, and check the row for the subsidiary shown in the load's **Invoice As** field.
</Tip>

## Key Concepts

**Invoice Update Mode** controls what happens when charges change after an invoice exists:

| Mode                | Behavior                                                                                                 |
| ------------------- | -------------------------------------------------------------------------------------------------------- |
| **Amendment**       | Updates the existing invoice in place. Cannot be used after any supplemental invoice exists on the load. |
| **Void and Revise** | Voids the prior invoice and issues a replacement.                                                        |
| **Supplemental**    | Keeps the original invoice and creates a new supplemental invoice for the delta.                         |

**Open invoice:** An invoice that has been generated but not yet fully submitted or settled through your configured delivery methods.

**Closed invoice:** An invoice that has been submitted and is no longer open for in-place revision.

**Supplemental delta:** Only the net change in line items since the last committed invoice amounts. Alvys does not re-bill charges already on a prior invoice.

## Steps

<Steps>
  <Step title="Set Invoice Update Mode to Supplemental">
    Open **Management** > **Company Profile** > **Invoicing Settings** for the subsidiary, or open the customer profile and set **Invoice Update Mode** to **Supplemental** for the correct **Invoice As** subsidiary.
  </Step>

  <Step title="Generate the original invoice">
    Release the load, then generate and submit the original invoice as usual. See [Invoice your customer](/en/help/accounting-settlements/invoicing-your-customer) or [Batch Invoicing](/en/help/accounting-settlements/batch-invoicing).
  </Step>

  <Step title="Change charges on the load">
    Update line haul, accessorials, fuel surcharge, or other billable amounts that differ from what was invoiced.
  </Step>

  <Step title="Regenerate the invoice">
    From the load, choose **Regenerate Invoice**. Alvys evaluates the current charges against what was already invoiced.

    * If the open invoice has not been submitted, Alvys revises it in place.
    * If the prior invoice was submitted or synced to accounting, Alvys creates the next supplemental (`-A`, then `-B`, and so on).
  </Step>

  <Step title="Review and submit the supplemental">
    Preview the supplemental PDF, confirm the delta amounts, then submit using the customer's configured delivery methods.
  </Step>
</Steps>

## When Alvys revises vs creates a new supplemental

| Situation                                      | What Alvys does                                                                        |
| ---------------------------------------------- | -------------------------------------------------------------------------------------- |
| Open invoice, not yet submitted                | Revises the open invoice in place                                                      |
| Invoice already submitted to the customer      | Creates the next supplemental letter (`-A`, `-B`, …)                                   |
| Invoice already synced to connected accounting | Creates the next supplemental letter; does not change the posted invoice in accounting |

You cannot create a new supplemental while another unsubmitted invoice is still open on the load. Submit or clear the open invoice first.

<Warning>
  After any supplemental invoice exists on a load, you cannot switch back to **Amendment** mode for that load's invoice history.
</Warning>

## Accounting sync

When your Alvys account is connected to external accounting software, each supplemental invoice is exported as its own invoice in that system.

* **Payments** from your accounting integration apply to the specific invoice they were recorded against — original or supplemental.
* A load moves to **Completed** only when every active invoice on the load is paid.
* If you change charges after an invoice has already posted to accounting, Alvys creates a new supplemental rather than editing the posted invoice.

For payment sync behavior and troubleshooting, see [Alvys payment synchronization for accounting integrations](/en/help/integrations/alvys-payment-synchronization-for-accounting-integrations).

## Limits & Behavior

* Supplemental mode requires **Individual** invoice type. It is not available for Summary Invoicing customers.
* You cannot use **Amendment** on a load that already has supplemental invoices.
* Alvys blocks supplemental generation when there are no pending charge changes.
* Changing invoicing settings after an invoice is generated does not automatically update existing invoices. Revert the load to **Released**, update settings, and regenerate if needed.

## Troubleshooting

### Supplemental mode is not being used

1. Open the customer profile and check **Invoicing Settings** for the load's **Invoice As** subsidiary.
2. Confirm **Invoice Update Mode** is set to **Supplemental** on the customer row, not only on the subsidiary default.
3. If settings were changed after the invoice was generated, revert the load to **Released** and regenerate.

### "No pending changes" when regenerating

Alvys found no dollar difference between current load charges and what was already invoiced. Update the billable amounts on the load, then try again.

### Cannot generate a supplemental — unsubmitted invoice exists

Submit or resolve the open invoice on the load before creating another supplemental.

### Settings on the load do not match the customer profile

Customer profile settings override subsidiary defaults. See [Invoicing settings not reflected on the load](/en/help/accounting-settlements/i-changed-the-invoicing-settings-but-it-s-not-reflected-on-the-load).

## FAQs

**Q: What is the difference between Amendment and Supplemental?**

**A:** Amendment changes the existing invoice in place. Supplemental keeps the original invoice and creates a new invoice for only the changed amounts. Once a supplemental exists, Amendment is no longer available on that load.

**Q: Why did my load get invoice `1001234-A`?**

**A:** `-A` is the first supplemental invoice on load `1001234`. Additional changes after that invoice is submitted create `-B`, `-C`, and so on.

**Q: Can I use Supplemental Invoicing with Summary Invoicing?**

**A:** No. Summary Invoicing supports Amendment mode only.

**Q: Which invoicing settings win — customer, subsidiary, or load?**

**A:** Customer profile settings for the **Invoice As** subsidiary take precedence over subsidiary defaults. Load-level snapshots do not override current customer or subsidiary settings.

**Q: What happens if I change charges after the invoice was sent to QuickBooks, Sage, or Business Central?**

**A:** Alvys creates a new supplemental invoice for the delta. The invoice already in your accounting system is not modified in place.

**Q: Do payments on the original invoice count toward the supplemental?**

**A:** Payments apply to the invoice they were recorded against. Paying the original does not automatically close an open supplemental.

**Q: Who can configure Supplemental Invoicing?**

**A:** Admins and Partner Admins can change invoicing settings in Company Profile. Users with access to customer profiles can set customer-level overrides.

## Go Deeper

* [Invoicing Settings](/en/help/accounting-settlements/invoicing-settings)
* [Invoice your customer](/en/help/accounting-settlements/invoicing-your-customer)
* [Batch Invoicing](/en/help/accounting-settlements/batch-invoicing)
* [Invoicing settings not reflected on the load](/en/help/accounting-settlements/i-changed-the-invoicing-settings-but-it-s-not-reflected-on-the-load)
* [Alvys payment synchronization for accounting integrations](/en/help/integrations/alvys-payment-synchronization-for-accounting-integrations)