All private companies are free to charge anything they want.
Only public funded projects have to be itemized.
I charge clients who are a pain in the ass more due to the burden they place on my staff.
It's how the world works.
At work we have a matrix to calculate our engineering fees based on the estimated construction cost.
We can add a multiplier to it if they are a difficult client or if they are wanting it done faster than normal.
We aren't selling hamburgers.
In a perfect world, your explanation would be valid. In this world, you have doctors,
dentists, mechanics, plumbers, air conditioning techs, you name it.....
Many of them will take the shirt off of your back if you let them. Perfect example: How many people go for a routine dental checkup, and get told that they need they're wisdom teeth out? How about a root canal? "But I'm not in pain, doc". "Well, you should get it done for preventative measures"...

In the hospital overnight? That's 100k that they charge your insurance company. And you guys wonder why insurance premiums go up all of the time.
We poo poo the mafia for all of the shit that they have done, when there are legal rackets going on, in broad daylight.