"[T]he Exchange Notices are a part of the Exchanges' verification process regarding eligibility for subsidies.... If an employee is determined eligible for Exchange subsidies, the employer appeal is the opportunity for an employer to correct information about employer-sponsored coverage offered to the employee ... The potential benefits of filing an appeal are two-fold: it can minimize the employee's potential liability to repay Exchange subsidies that he or she was not eligible to receive and can help protect the employer from being incorrectly assessed an excise tax under Code Section 4980H ... Each State Exchange may create its own appeal process or choose not to establish an appeal process and have the HHS conduct the appeal in accordance with the Federal Exchange appeal process."