Evidently the A330 pitot and the 727 pitot (NWA accident) behaved differently when iced up. The 727 was climbing, low-altitude pitot air was trapped in the system, and as static pressure dropped with altitude, the IAS display kept increasing.
But this is explained by the fact the 727 crew DID NOT TURN ON pitot heat at all, so both the ram and drain ports were blocked.