Arbitration — Procedure — Time-limits fixed in Charter establishing Arbitral Commission — Impossibility of changing such time-limits on basis of Commission's Rules of Procedure — Convention on the Settlement of Matters Arising Out of the War and Occupation, 1952–1954 — Appeals to Arbitral Commission under Chapter Ten, Article 12, paragraph 2, second sentence, of Convention — Retroactive application of appeal provisions — Whether permissible — Change of law on appeals — Admissibility of certain appeals under new law — Inadmissibility of other appeals — Whether constituting discriminatory or unequal treatment.