Mail Order in Formulary

We’re currently mapping a formulary to Coverage Plan (List) and FormularyDrug (MedicationKnowledge). The CoveragePlan profile has the mail order indicator (Yes/No) and it appears to be required under the usdf-DrugTierDefinition-extension. However, mail order is not a “plan-level” attribute. It is an attribute of the drug. e.g. I’m on Medicare Advantage plan and I can get Atorvastatin through mail order but I can’t get Adempas via mail order. Both drugs are in the same formulary. Has anyone come across this issue and, if so, how did you handle it?

I added this as a question/answer on the Formulary zulip stream.