Please update the documentation on the US Core Procedure Profile, in the Must Have section 12.136.1.1 bullet 4. surrounding the 'perfomed' attribute to include a conditional statement surrounding the rule: 

us-core-7: Performed SHALL be present if the status is 'completed' or 'in-progress'

Otherwise, it's not completely obvious in the documentation that the 'performed' attribute is not required when the status is 'not done'.