It means that the normally required backup for payment is not there. It pales to the mispaid invoices in Medicare/Medicaid
You are focusing on the chump change because it fits your political bent
https://www.google.com/webhp?sourceid=chrome-instant&ion=1&espv=2&ie=UTF-8#q=Fraud+payments+per+year+medicare&*
In fiscal 2014 alone, 22 agencies approved improper Medicare, Medicaid and Earned Income Tax Credit payments totaling an astounding $124.7 billion—an increase of $18.9 billion or 15 percent from the previous year, according to a new report.
Those overpayments accounted for over 75 percent of the estimated government-wide overpayments or improper payments.