(b) The principles for reimbursement require the apportionment of the provider’s allowable costs in accordance with two prescribed methods:

1. (1) The ‘‘Departmental Method’’ shall be used by all hospitals having more than 99 beds, exclusive of bassinets in the nursery, on the first day of the cost reporting period.

2. (2) The ‘‘Combination Method’’ shall be used by all hospitals having less than 100 beds, exclusive of bassinets in the nursery, on the first day of the cost reporting period. The prescribed methods of apportionment shall be defined as follows:

   1. (i) Departmental Method. The following provisions shall apply in determining the cost of services applicable to the Medical Assistance Program:

      1. (A) Inpatient routine services. Cost for inpatient routine services shall be determined as follows:

         1. (I) General care units. Average cost per diem for general routine patient care areas.

            (II). Special care units. A separate average cost per diem for each intensive care unit, coronary care unit, and other special care inpatient hospital units.

      2. (B) Ancillary services. The ratio of Medical Assistance patient charges to total patient charges for the services of each ancillary shall be applied to the cost of the department.

   2. (ii) Combination Method. The following provisions apply in determining the cost of services applicable to the Medical Assistance Program:

      1. (A) Inpatient routine services. Costs for inpatient routine services shall be determined as follows:

         1. (I) General care units. Average cost per diem for general routine patient care areas.
         2. (II) Special care units. A separate average cost per diem for the aggregate of intensive care, coronary care, and other special care inpatient hospital units.
      2. (B) Ancillary services. The ratio of Medical Assistance patient charges for all ancillary services, to total patient charges for all such services shall be applied to the total cost of all ancillary services.