For years I thought our service department made money, then I was challenged to break out the cost of operating the service department. We use to do a million in sales doing RNC. We had one person in the office, part time. To do the same amount of sales in service only, not counting replacements, you will have at least triple the overhead. The dealers in my mix groups get upset when I tell them they are losing money in their service departments. If you are not departmentalizing, you have no ideal what your overhead is for the service department. We made changes and we now know where to make adjustments.