doctors have to submit large bills to up the ante for what portion they get paid. Insurance companies pay our docs next to nothing as reasonable and customary compared to what they bill. Most likely out of that $425 the doc will only get $75 but since your sister paid out of pocket the "real" cost is $50. Honestly with the cost of med mal insurance, running a practice and keeping staff I don't know how these docs pay their school loans off!
Glad I had insurance anyway since my out of pocket was $3600 last year. Compare that to $50K!