The reason the labor price is so high is probably due to the make of the car. I know my wife's Pontiac Grand Prix is a bugger to work on. Everything is placed so that I have to disassemble needless things to work on a problem. In fact I have to remove the washer fluid holder in order to change her battery. That would be my best guess at your problem. An even better example would be when I changed the oil pan gasket on my pickup. If I would have taken it to a mechanic it would have cost approx. $650!
The gasket was only $30. But, in order to change it I had to loosen my engine mounts, use a cherry picker to tilt the engine block forward, and then I was able to work on what I needed. But, you have ran into some luck. Labor prices are very variable, and you should try some other estimates. Good Luck!