Item Qualification Analysis Report - Difference between "Extended Cost" and "Value Added"

Summary:

What is the Difference between column "Extended Cost" and "Value Added" in the last section of Item Qualification Analysis Report? 

Content (required):

In the last section of Item Qualification Analysis Report, we can find two columns "Extended Cost" and "Value Added". I can understand that "Extended Cost" is generally "(material cost + material overhead)*quantity" for components. As to "Value Added", I thought it is supposed to be material overhead but our test results show it is always the same with "Extended Cost". That makes me wonder why we need two columns showing the same value. Any advice will be appreciated.