"The proposed rule does not offer any specific guidance on how a covered health insurance issuer's required compliance would apply to its services as a third party administrator for a self-funded group health plan.... This means that insurers participating in the ACA Marketplaces that also offer coverage to employers in the group market, and those who act as TPAs for self-funded plans, may need to apply these rules to their group insurance coverages and even to the plans for which they serve as TPAs. This is a potentially very broad-sweeping rule that could change what employer plans have to cover."