It seems so obvious to constrain your company with a final price before you begin to incur any costs, yet this practice is not widely followed, despite its proven successes. Costs are, no doubt, important to consider, but the crucial distinction is when they are considered. By its very nature, cost accounting is a historical function, but what is important for pricing are planned costs, not past costs. Furthermore, cost accountants usually pay far too much attention to sunk costs, which should have no influence over pricing or value considerations.