QuickBooks Desktop comes equipped with a wide array of reports that you can run to view a snapshot of your business. I'm glad to hear that you've been making the most of these reports in both companies that you work for, and I want to make sure that you're able to see the data that these reports are intended to show.
The Sales by Customer Summary report is intended to show you the total of your sales for each customer based on sales transactions such as invoices and sales receipts. This report has the added bonus of offering the option to display amounts in transaction currency instead of home currency, so I can see how helpful this is for you.
Since you're not seeing totals, which is the intended purpose of this report, it leads me to believe that you may be running a different report in one of your companies. Double check that you are indeed running the same report, and close and re-open QuickBooks as an added means of troubleshooting.
There isn't a reason why the same report should act differently in different companies, and there aren't any customizations that would allow you to change the primary function of a report, such as showing totals. If the suggestions above don't help you to view the totals in the Sales by Customer Summary Report, the next step would be to reach out to our awesome support team who can do a screen share with you in order to get to the bottom of this issue.
Support is available from 9 am to 8pm EST on Monday to Friday for QuickBooks Desktop Pro, Premier, as well as Enterprise. Reach our team of highly trained agents at 1-877-772-9158. Here's where you can read more about the Intuit QuickBooks Desktop software support policies.
I'm confident you'll get to the bottom of this soon! Have a great day.