Why is there a difference between Total Open Sales Orders by Customer and Total Open Sales Orders by Items reports, in QuickBooks Desktop?

@CFernandez  Off the top of my head, that sounds like there are Items that are not associated with a Customer.

If that is the case, I would expect that the Open Sales Orders by Item report would have blank spots in the Name column. Is that what you see?

Here are a few potential reasons why we see the difference between the Total Open Sales Orders by Customer report and the Total Open Sales Orders by Items report in QuickBooks Desktop, CFernandez. I'll be here to lay out these pointers for you.

If you have partially invoiced some sales orders, those partially fulfilled orders may not show up on the Open Sales Orders by Customer report, even though they still have open items.

We can also double-check if you have any custom dates, filters, or customization applied to one report. See this page for your guide: Customize reports in QuickBooks Desktop.

Furthermore, tax amounts can also differ from the totals of both reports. In this case, we can click each item on the report to see how much tax was applied. I've added this screenshot for your reference:

Then, looking at the sales order number 7005, the amount that differs both report is the tax amount.

In addition, I'll be adding this article for your guide on how to save custom-generated reports: Create, access, and modify memorized reports.

We are still available to assist you further regarding this report's concerns in QuickBooks Desktop. Keep us notified by adding your comment below.