I think they are on the spot for pricing....

I mean you ARE throwing them a 23 years old MB... they KNOW it's not going to go as smooth as the book says.

I wouldn't charge any less for that job if I had a shop.

take, for example, a simple alignment job:
1984 Toyota Corolla SR5 with a S2000 engine in it - took the owner 2 hours - charged me 80 bux to align the car properly...in the whole time you watch him it's like some sweat shop worker - swearing, sweating, flaming (literally, at my stuck tie rods) WD40ing....
1995 Mercedes Benz C220 - took the owner about 20 minutes - charged me 40 dollars....he just stood there and turned the tierod about 8 rounds and it was all good.

in the end you probably got a better deal at that price.