---
title: "Bill seat and device changes"
description: "Choose how devices and people that come and go during a period are billed, by snapshot, peak, or daily proration with a true-up on the next invoice."
url: "https://support.outpostplatform.com/msp/usage-methods/"
product: "depot"
type: "how-to"
status: "draft"
ai_summary: "MSP plan. Usage method on counted agreement lines: Snapshot (count when the invoice is built), Peak (highest daily count in the period), Daily (each device or person for the days present). Invoices bill in advance at the snapshot count; peak and daily add a Usage true-up line on the next invoice. Set at practice, client, or line level. Daily counts are taken once a day."
availability:
  plans: ["msp"]
  permission: "psa:write"
  preview: false
source: "https://gitlab.com/outpostplatform/docs/-/edit/main/src/content/docs/msp/usage-methods.md"
license: "CC BY 4.0"
---

# Bill seat and device changes

Devices and people join and leave a client part way through a billing period.
The usage method decides how those changes are billed. This page explains the
three methods and shows where to set them for your whole practice, for one
client, or for one agreement line.

## Before you begin

- The practice default needs `psa:admin`. A client's default and a line's
  method need `psa:write`.
- The method applies to counted lines only: **Per device**, **Per user**, and
  **Per seat**. See [Bill by device type and seat](/msp/device-and-seat-lines/).

## The three methods

Invoices are billed in advance. Outpost drafts each invoice at the start of
its period, so it always bills the count on the day it is built. With peak or
daily, the next invoice also carries a **Usage true-up** line for the
difference between what was billed and what was used.

| Method | Measures | True-up on the next invoice |
| --- | --- | --- |
| **Snapshot** | The count on the day the invoice is built. | None. This is the default, and how agreements billed before usage methods existed. |
| **Peak** | The highest daily count in the period. | The peak minus the count billed, times the unit price. |
| **Daily** | Each device or person for the days they were present. One device present for 10 days of a 30-day period counts as `0.3333`. | The measured quantity minus the count billed, times the unit price. |

A true-up can be a charge or a credit. With daily, a client that removed
devices during the month gets a credit on the next invoice. The unit price is
the one in force at the start of the period being measured, so a price
increase never reprices a period billed before it.

Outpost takes the client's counts once a day. A day with no count, for example
while the server was down, carries the day before's count forward.

### Worked example

A workstation line bills $35 per device with the daily method. On 1 October
the client has 20 workstations, so the October invoice bills 20. On
21 October two workstations are retired, so for the last 11 days of the month
the client has 18.

- Measured: 20 for 20 days plus 18 for 11 days, divided by 31 days, is
  `19.2903`.
- The November invoice bills 18 workstations in advance, plus a **Usage
  true-up** of `19.2903 - 20 = -0.7097` times $35, a credit of $24.84.

With peak, the same month measures 20, so the true-up is zero.

## Set the practice default

1. At the practice level, select **Client billing** > **Settings**.
2. Under **Invoicing**, in **Usage method**, choose **Snapshot**, **Peak**, or
   **Daily**.
3. Select **Save settings**.

## Set a client's method

1. In the client's workspace, select **Client billing** > **Billing profile**.
2. Under **Overrides**, in **Usage method**, choose a method, or **Use the
   practice default** to inherit.
3. Select **Save**.

Under **What this client is billed on**, **Counts devices by** shows the
method in effect and whether it comes from the practice default.

## Set one line's method

1. Open the agreement.
2. Under **Lines**, in the line's **Usage method**, choose a method, or **Use
   the client's default** to inherit.
3. Select **Save**.

The most specific setting wins: the line, then the client, then the practice.

## What to expect when you change the method

- The first invoice after you switch a line to peak or daily bills in advance
  as usual. Its true-up arrives on the invoice after that, once a whole period
  has been measured. The **Next bill** card says when there is no earlier
  invoice to settle against yet.
- Switching back to snapshot still settles the last peak or daily period on
  the next invoice.
- The overage part of a **Per seat** line is always billed at the snapshot
  count. Peak and daily true up the seat count only.
- A true-up credit larger than the invoice it lands on is capped so the
  invoice stays at zero or above. The rest is left off, and the estimate says
  how much, so you can issue a credit note. See
  [Invoice clients](/msp/client-invoicing/).

## Verify

On the agreement's **Next bill** card, each counted line shows its method
under **Counted**, and a **Usage true-up** line appears once a peak or daily
period has been billed. See [Check a client's next bill](/msp/next-bill-estimate/).

## Next steps

- [Add discounts and annual price increases](/msp/discounts-and-price-increases/)
- [Check a client's next bill](/msp/next-bill-estimate/)