We go by book labor.
My guys get paid by book labor hours.
I sure cant fault a man that beens doing it for 20 years and has 20,000$ in tools for being able to take out a engine is 45 mins when it calls for 7 hours. The only way he gets paid well is to beat the book.
We charge almost 80$ a hour as well.
I have zero problem with them charging book rate. That is the way it works.
My only disagrement is that you were not stated a cost before work began and a lack of discussion that hey sometimes we find things broken that you cant see from the outside, I wont just fix it with out your permission but the estimate could need more parts.
The service writer should never of asked the tech how long it would take. Thats not the way it works.
The shop did not spend a huge amount of money on building a shop, air system, electrical system, massive amounts of supplies, money on lifts, multiple people, insurance, and such for the fun of it.
I do most of my work myself, because I can.