All types of Advance Directive and POST documentation will be recorded using the Advance Directive Observation.  To avoid Template bloat, we didn't need to define a different template for recording the existence of POLST document. Structurally it would be identical, we just needed to open up the value sets used with the structure. Add more categories besides The categories of advance directives source documents could include, but are not limited to, the following:

Personal advance care plan
Living Will
Durable Healthcare (Medical) Power of Attorney
in the purpose statement. Missing ones are Combined Living Will and Durable Healthcare (Medical) Power of Attorney and Portable Medical Order.Explain the whole hierarchy under Health Directive

The complexity of the description of what type of content was in the document is handled by binding to a grouping value set which covers POLST content is a separate VS from the Advance Directive type of content. 

If this design is not considered optimal, then we'll need to consider making a separate template for POLST Observation to be used in an Encounter or Patient Summary document type. 

These needs have surfaced recently due to work to align with the FHIR ADI IG that is looking at all three types of Advance Directive content:  Person-authored documents, Provider Authored Portable Medical Orders, and Encounter Summary information.