Adding Cost Center Reporting to the Microsoft 365 Licensing Report

Different Forms of Cost Centers

On June 20, I announced version 1.9 of the Microsoft 365 Licensing Report. A month later, version 1.92 is available for download from GitHub. This version adds support for reporting licensing costs by cost center. Here’s how it works.

Ever since Exchange Server added a set of 15 custom attributes to mailboxes, organizations have used the attributes to hold all kinds of information. Cost center numbers come in different formats. In Digital Equipment Corporation, the numbers (or rather, designation) were values like 8ZW and 9HPE. In Compaq and HP, the values were more like 1001910. In any case, organizations often store cost center values in custom attributes to allow a more precise assignment of costs than is possible using standard Entra ID account properties like city, department, and country.

For cost center reporting to work, it’s obvious that accurate cost center numbers must be present in Exchange mailbox properties. Sometimes cost centers are added when users join an organization and receive a mailbox and are never updated afterwards. In other instances, organizations have synchronization mechanisms in place to ensure that if a change is made to an employee’s cost center (usually in a HR database), that change also happens for mailbox properties.

It might also be possible to implement cost center reporting based on managers (if managers manage cost centers). To do this, the script would have to find all the managers and assume that any direct reports are in the same cost center as the manager. I discounted this method and chose the simpler approach of using cost centers stored in a custom attribute, but it wouldn’t be difficult to code because Entra ID links stores details of the manager for each user account. Storing a manager for an account is not mandatory, so the same problem of data accuracy and availability might be present.

Microsoft 365 Licensing Report Script Changes to Support Cost Centers

The script supports cost center reporting through a variable called $CostCenterAttribute, which holds the name of the custom attribute to use. The name stored in the variable is the Entra ID property name rather than the Exchange name, so it’s a value like extensionAttribute1. If $CostCenterAttribute is not defined, the report doesn’t attempt to generate any information about licensing cost per cost center.

Exchange Online synchronizes the values of the mailbox custom attributes to the Entra ID user accounts of the mailbox owners. The custom attributes are stored in a property called OnPremisesExtensionAttributes. The Get-MgUser command to fetch user account details is amended to include OnPremisesExtensionAttributes in the set of retrieved properties. A set of cost centers found in user accounts is derived from the information retrieved by Get-MgUser.

When scanning user accounts for license information, the script extracts the cost center for each account and stores it along with other licensing data in a PowerShell list. This allows the report to later loop through the set of cost centers found in user accounts and calculate the licensing spend for each cost center, much like the licensing spend analysis done for departments and countries.

Reporting Licensing Spend by Cost Center

The script then outputs the cost center licensing spend analysis along with the other spending data in the summary part of the report (Figure 1).

Custom Attributes Open Up Lots of Opportunity

In this instance, the Microsoft 365 licensing report uses a custom attribute to store a cost center value. It is easy to see how custom attributes could be used for other analysis. For example, if a custom attribute held details of major projects, you could report the licensing spend for each project. All of this is basic PowerShell, so feel free to experiment!

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