Routine v. Ancillary v. Capital costs
I came across a clear distinction between these areas of costs in a 1998 Federal Register entry implementing the SNF PPS. It states:
In general, routine costs are the costs of those services included by the provider in a daily service charge. Routine service costs include regular room, dietary, nursing services, minor medical supplies, medical social services, psychiatric social services, and the use of certain facilities and equipment for which a separate charge is not made. Ancillary costs are costs for specialized services, such as therapy, drugs, and laboratory services, that are directly identifiable to individual patients. Capital-related costs include the costs of land, building, equipment, and the interest incurred in financing the acquisition of such items.
Source: Federal Register