Where any time limit fixed in this Treaty or the Regulations is not met because of interruption in the mail service or unavoidable loss or delay in the mail, the time limit shall be deemed to be met in the cases and subject to the proof and other conditions prescribed in the Regulations.
(2) (a) Any Contracting State shall, as far as that State is concerned, excuse, for reasons admitted under its national law, any delay in meeting any time limit.
(b) Any Contracting State may, as far as that State is concerned, excuse, for reasons other than those referred to in subparagraph (a), any delay in meeting any time limit.