What external failure cost is very difficult to estimate? Warranty Costs Cost of service malls Sales returns and allowances O Lost profits from lost customers Decreased profits due to lost customers as a result of a company having a reputation for poor quality are an example of appraisal costs. external failure costs. prevention costs. internal failure costs. When deciding to buy a new accounting system, the irrelevant cost is the cost of training staff to use the new system. The increase in maintenance fees for system upgrades for the new system compared to what was being paid for the existing system cost of the new software the purchase price paid for the old software. The cost of a successful lawsuit against a company for selling defective products is an example of a(n) external failure cost. prevention cost. appraisal cost. internal failure cost