Otherwise known as the Independent Contractor Estimate, target rates and engineering estimates are inherently unreliable as a price analysis metric. Why? Because the data that make them up is, in and of itself, unreliable. For instance, Salary.com - indirect rates floating in a vacuum. This is not the stuff of winning bids.
Ask yourself this - how many contracts has your company won using made-up target rates? Of that percentage, how many empty buckets filled and loss leaders turned a profit?