When the qualification of an addressee to receive restricted matter within the conditions in this chapter and DMM 601.11.4 is in question, a postmaster may require the mailer or addressee to furnish a written explanation of the addressee’s eligibility and/or the item’s mailability. If the explanation is not satisfactory or when uncertainty remains, the postmaster may forward the explanation along with a statement of the facts to the PCSC for a ruling.