While I agree with fast + time wasted = normal speed, in reality it is not the wasted time that plays the role. In most companies developers don't have a fixed 8 hour job and most of them work more than 8 hours a day on a routine basis. I have seen managers who valued the total time spent working more than the actual work accomplished. So a developer who works about 8 hours a day was ranked below someone who spent 10-12 hours a day working even though it was the former who was accomplishing more tasks.