We have two poorly defined extensions http://hl7.org/fhir/StructureDefinition/relative-date and http://hl7.org/fhir/StructureDefinition/cqf-relativeDateTime. The context of use of the relative-date extension is specified as date and dateTime, but it's trying to describe both definitional use - where the context would be different to that. 

I believe that this extension should focus on noting that this specific date/time is because of a relationship to an event, and leave scheduling management to a different extension, because although there's some overlap, there's also very significant differences, and trying to manage both in the same structure adds additional confusion to an area where there's already considerable potential for confusion. 

For this extension, we should add a text description, and we should significant improve the definitions of the elements in it