Hi, I am a Johnson & Johnson employee and I received an additional bill from my health...

Hi, I am a Johnson & Johnson employee and I received an additional bill from my health care provider for services rendered to a family member in January ****. I paid the original bill for January service for an invoice received in March ****. I have subsequently received an additional bill from my service provider for the January service in an invoice dated June ****. There are two Explanations of Benefits (EoB) from Aetna for the January service showing two different "Member Rates". In speaking with Aetna, I learned that Providers negotiate contracts with Aetna to define the Member Rates and that based on the terms of the contract Aetna allow the Providers to re-bill customers the top-up for increases in these retroactive rate adjustments. I am concerned that I have not seen any language available on the J&J benefits portal or on the Aetna site that states that such retroactive rate adjustments could happen. In my particular case, the new rate for the service was double the original. There is no transparency to us (Aetna's customer) for these rate adjustments and had led (in my case) to paying double than the original service was quoted as costing. Are there terms in J&J's contract with Aetna that allow for this practice (that are not available to view for employees taking out a policy) or is this just standard insurance industry custom and practice?