There is no "Costs" column. There is the Cost column and then Cost1, Cost2, Cost3, etc. When I create a simple project add the Cost column to the view and add costs and durations - I see the data in the Task Usage view and it exports using the Excel Visual Report - Cost Report. Do you see data in the pivot table exported to Excel if you put data in the Fixed Cost field?

Do you have Service Pack 1 installed to Project 2010?