jryden: It's true that arpa lost to a stronger player, but this is not relevant for the Sonneborn-Berger calculation. What matters is that alanback defeated a stronger player.
arpa's and redsales's S-Bs were computed incorrectly. The correct result is:
(kaŝi) Se vi volas saluti iun en ties denaska lingvo, provu nian 'vortaron de ludanto', en la ligo "pli pri lingvoj" sub la flagoj. (pauloaguia) (Montri ĉiujn konsilojn)