Thank you for reaching back to us, @buzz21.

I appreciate you for trying all of the steps suggested by my colleague. Let me help you locate and add the Service date in your Sales by Customer Detail report. Here's how, and please see the screenshots below.

1. Go to the Reports tab.

2. Search the Sales by Customer Detail.

3. Choose the date period, then press the Run report button. 

4. Click the Customize option to filter the transaction to Invoice only.

5. Select the Small gear icon, then click the Show More option. 

6. Check the Service Date option, then select Reorder columns.

7. Click Run report.

Once done, the Service date column will show on your Sales by Customer Detail report.

You can read this article to learn specific ways to customize your reports: Common custom reports in QuickBooks Online.

Feel free to click the Reply button if you need further assistance on managing your reports or invoices. Stay safe!