There are two different methods to generate a report that shows the profit calculation per invoice in QuickBooks, @TFS2.

The first method is to use the Project, which has a Project Profitability Report. Here's how:

1. Go to Projects, then New Projects.
   

   

2. Enter your Project details, then click Save.
3. Once done, look for the Add to project dropdown in the upper right corner of your screen.
   
   
4. You can now add an invoice and an estimate. Ensure to select the project you created in the Payee and Customer details, then hit Save.
5. After that, Go to the Project Reports.
   
   
6. Select the View option in the Project Profitability report.
7. To display specific invoices and their dates, choose Custom in the Report Period and filter by the dates you need.

The second one is to generate and customize your Profit and Loss report if you use COGS for inventory items. Ensure you enter the purchase cost and then the price rate to calculate the cost of goods sold. Here's how:

1. Go to Reports.
   
2. In the search bar, type in Profit and Loss report, then click it.
3. In the Report period, select Custom dates and choose what date you want to see. 
   
4. In the Filter section select the specific customer for that invoice.
   
5. Once done, hit Save.

After getting the net income, you can use the amount in calculating when paying the commission based on profit. 

If you'd like to explore Class Tracking and Location Tracking to track sales by employee, sales rep, check out this guide: Track sales commissions in QuickBooks Online.

On top of that, this article guides you on how to keep your personalized reports in QuickBooks Online once you have the perfect set of filters for future use: Save a customized report.

Respond in the thread below if you have any other questions about reports in QuickBooks Online.