Fair enough. I guess we're using different definitions of the start and finish of the job. Four hours is about how much wrench slinging is required for this job. I agree about the remaining time the job will consume, but don't really look at it as work. Any task which permits you to consume a coffee/coke/beer I don't include in my "work" time.
If it makes you feel better, I stated at 8AM and finished at 3PM. In between I watched some TV, ate lunch, ran to Lowe's for pool chlorine, hosed out the garage, talked on the phone, idled the car and topped up the coolant, etc. Didn't drink any beer - my loss.