This is the ValueSet that contains all the codes in RTPBC Billing Unit Value Set (http://hl7.org/fhir/us/carin-rtpbc/ValueSet/rtpbc-billing-unit) and RTPBC Billing Unit Value Set (http://hl7.org/fhir/us/carin-rtpbc/ValueSet/rtpbc-billing-unit). E.g. what you have to deal with if you get resources containing codes in either of them