> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.plexflow.ca/sitemap.xml
> Use this file to discover available pages before exploring further.
> Pure-Markdown content can be obtained by appending a '.md' suffix to the content URLs listed in the sitemap (without the trailing slash).

# Commercial leases - How to add a one-time amount in Plexflow

In some situations, a lease may require the addition of a **one-time amount** on a specific date.
For example: the **annual allocation of municipal taxes**, a **maintenance fee adjustment**, or any other exceptional expense.
This lets you add a **single invoice** without changing the lease’s regular billing calendar.

⚙️ **Preliminary note**
The Plexflow system was not originally designed for managing **commercial leases**.
However, several features have been added to **allow greater flexibility**, in particular to add **one-time amounts or unique adjustments**.

### Steps

#### Step 1 – Go to Rent Details in question

Go to the **Rents** section, then select the **active lease** for which you want to add a one-time amount.

#### Step 2 – Add a new invoice

In the **Upcoming Invoices** section, click the **Add ➕** button to create a **one-time invoice**.

👉 If you are not sure of the difference between an invoice and a collection, see this article:
[Understanding the rent billing process in Plexflow](https://help.plexflow.ca/fr/article/comprendre-le-processus-de-facturation-des-loyers-dans-plexflow-1xh1csf/)

![Upcoming Invoices section with the Add button](https://storage.crisp.chat/users/helpdesk/website/-/9/9/5/a/995a701e47028800/etape-2_1xwc3xp.png)

#### Step 3 – Choose a date different from an existing rent

⚠️ **Very important**
The system **does not allow two invoices on the same date**.
You must therefore choose **a different date** from your regular rents (e.g. **January 2** if the regular rent is on **January 1**).
Then enter the **desired amount**.
👉 If this amount must include taxes, enter the **total amount** directly.

![Window to add a one-time invoice on a different date](https://storage.crisp.chat/users/helpdesk/website/-/9/9/5/a/995a701e47028800/etape-3_1cde8it.png)

#### Step 4 – Edit the invoice information

Once the invoice has been added, you can adjust the details:

- the type of service or rent
- **Exact amount**
- the applicable tax (**No tax**, **TPS 5%**, **TVQ 9.975%**, or **TPS&TVQ 14.975%**)
- **Payment method and internal note**

![Invoice details to adjust after adding a one-time amount](https://storage.crisp.chat/users/helpdesk/website/-/9/9/5/a/995a701e47028800/etape-finale_1y113t8.png)