Final answer:
In cases where a patient has both primary and secondary commercial health insurance, the primary insurance is billed first, and then the secondary may cover remaining costs. The two are not submitted as a single payment, and the primary always precedes the secondary.
Step-by-step explanation:
When a patient is covered by the same primary and secondary commercial health insurance plans, the situation dictates that the primary insurance will be billed first. Any remaining balance after the primary insurer has paid its portion will then be submitted to the secondary insurance. The secondary insurance may cover some or all of the remaining costs, depending on the policy's benefits. The two insurances are not billed together as a single payment, and the secondary insurance is never billed before the primary insurance.