formula giving wrong result sometimes?

Hello,

I have made up a workbook to keep track of sales. It has the sale price plus shipping less fees and it works but one entry is giving a final amount which is off by a penny and I was wondering why.

I have attached the workbook with the formulas used to get the results and highlighted the one that is giving the incorrect final amount. If I use a calculator the result is correct and there is no need to round up or down so I don't understand.

Any assistance would be greatly appreciated.