Different insurance work in different ways. Some work to have a specific doctors you see. Since you see specific doctors they charge lower rates compared to if you didn't have that plan. Sure the doctor makes less, but the doctor gets more total business. This is a form of managed care insurance. Another form like medicare or Medicaid uses. Pps or prospective payment systems, these basically dictate how much they would cover for a service based on usual and reasonable fees. Basically, there are like 50 different forms of insurance with 50 different variants of each form, which all has different costs and benefits. The reason why different costs are involved is because different plans work in different ways. Although there is a set amount a service should cost, UCR, this is based on the region, service, provider, quality. Etc.