; and (2) differentiate as appropriate to recognize variation or higher costs related to— (A) aviation instrument flight control; (B) provision of care to critically ill or injured patients; (C) the provision of services in geographically isolated areas; and (D) the provision of care to uninsured individuals. (b) Recommendations As part of the report submitted under subsection (a), the Medicare Payment Advisory Commission shall provide recommendations on whether changes should be made with regard to reimbursement of air ambulance providers and suppliers under title XVIII of the Social Security Act based upon the data submitted under paragraph (18) of section 1834(l) of the Social Security Act, as added by section 4, taking into consideration variables affecting payment adequacy under such title for and its impact on Medicare beneficiaries, including— (1) whether payment under such title is sufficient to ensure access to air ambulance services or should be altered, including whether payment should be higher for air ambulance providers and suppliers— (A) with higher levels of clinical capability to serve the most critically ill and injured patients; and (B) that utilize advanced and expense avionics such as Instrument Flight Rules; (2) whether uncompensated care borne by air ambulance providers and suppliers impedes access; (3) the degree to which there is variation in the utilization of air ambulance services on a per capita and per transport basis, including whether the undersupply or oversupply of helicopters or fixed wing aircraft in a geographic region affects access and the volume and adequacy of payments under such title with regard to such utilization; (4) the degree to which membership programs are utilized by air ambulance providers and suppliers to sustain their operations, and if revenue from membership programs is used to reduce their costs or provide capital funding, and whether such programs are beneficial to Medicare beneficiaries