I see where Mike is coming from in regards to the labor RATE, we are talking about the TIME though, which Mike mentioned.
Yes, there are Labor Time Guides, they are really set up more for warranty work, but we do at least refer to them. We need labor time guides for older cars too, because MB does warranty parts for 1 year unlimited mileage in most case, sometimes more, such as a new/reman engine, where I think it's like 3 years plus a mileage restriction. If the engine, or some other 1 year warranty part fails, we need the time guide, because that's all MB is paying us. Now, not everything is covered. it's pretty complete, but even on a new car, not everything is covered, we usual charge "open" time for that, BUT we need to prove it by using a time punch system to prove that if we charge MB 1.5 hours to do a job, that this is how much time we spent on it. YES we hope to get jobs that are in the time guide as paying MORE time than we have into the job, as we can get paid for MORE hours than we were actually working. As long as the job was perfomed correctly, we can sleep well at night and not feel anyone was cheated.
With an older car like this, to do something like replacing a brake line (assuming the main steel line, not a rubber hose (those are fairly easy usually) I'm pretty sure it's one of those parts that may not be in the time guide. You also have to take into account the time guides were published with a relatively new car, not really corroded or worn out. If I get into a situation like this (an older car with lots of rusty parts, not saying yours is) then the timeguide, even if the job is in there, can pretty much be thrown out the window. MB didn't take into account breaking bolts, stripped out hydraulic fittings and the like when publishing these things.
On the brake pads, we have set times we charge for items like this, to allow the service advisor to quote prices easier, it's a time we in the shop aggree to charge. If again you get into an unusual problem due to wear or rust, it may have to be upped, but we would let the advisor know before getting in too deep. On rear brake pads (pads only) we charge .8 for a set of front or rear pads. Rear rotors add alot to the price, especially if the rear parking brake linings are shot, then you may also be looking at parking brake cables, etc. I am interested in knowing just what was replaced and I can comment further on what you specifically were charged. I would hesitate to criticize the amount of time you were charged without having the whole story.