There can be only one formatCode per documentReference. The format should then be 0..1, not 0... This format indication is about the whole DocumentReference, not specifically that instance of content. The reason for content to be 1.. is that there might be multiple mime-type encodings; not that it would be different formats. This is the rules in XDS, and therefore the constraint would be placed by that Profile. So if there are other use-cases that have not surfaced in IHE, then please explain the use-case. Recognizing that multiple DocumentReference entries are also possible and would be recommendation from IHE.