Job Detail Report with Negative Unbilled Costs

I have Negative unbilled costs on a Job from negative lines.  When I run the Job Detail report(Jmdetl.frx) the Billed Costs look wrong. 

Solution

It is the double negative in the math that has made it look incorrect in this case.

Total Costs LESS NEGATIVE Unbilled Costs = Billed Costs

$470.54 - - $174.46 = $645;

Or

$470.54 +  $174.46 = $645;