Section 890.906 - Retired enrolled individuals coinsurance payments(a) A retired enrolled individual's coinsurance responsibility for inpatient hospital services is calculated in accordance with the plan's contractual benefit structure and is based on the amount determined to be equivalent to the Medicare part A payment under the DRG-based PPS.(b) A retired enrolled individual's coinsurance responsibility for physician services is calculated in accordance with the plan's contractual benefit structure and is based on the lower of the actual charges or the amount determined to be equivalent to the Medicare part B payment under the Medicare Participating Physician Fee Schedule for Medicare participating physicians and the Medicare Nonparticipating Physician Fee Schedule for Medicare nonparticipating physicians.60 FR 26668, May 18, 1995