In broader medicine, one basis that can lead to the above sort of dynamic is compassionate protocol ("we are losing a little money on this deal, but you are in-need and we're here to help everyone"), as opposed to greed protocol ("we medicos are here for the big insurance money, and only charge the True Low Cost when forced").
And on balance, the nature of the people who choose the occupation of medicine tends towards the former.
This sounds more like tax evasion than paperwork avoidance.
Just means I'm paying them directly instead of making them deal with my insurance.
I've had providers tell me they'd have been happy to charge me less, making less than their insurance reimbursement, but not have to mess w/ billing my insurance, but they were unable because their contract with my insurer did not allow it.
Are pennies okay? Sorry, they're not rolled. Just let me know if it's not enough.