"[A]ssuming full collections of risk corridors charges for the 2014 benefit year, insurers will be paid an amount that reflects a proration rate of 12.6% of their 2014 benefit year risk corridors payment requests. The remaining 2014 risk corridors payments will be made from 2015 risk corridors collections, and if necessary, 2016 collections. In the event of a shortfall for the 2016 program year, [HHS] will explore other sources of funding for risk corridors payments ... This includes working with Congress on the necessary funding for outstanding risk corridors payments.... HHS is recording those amounts that remain unpaid following our 12.6% payment this winter as fiscal year 2015 obligation of the United States Government for which full payment is required."