Я и не говорил что школа одна, хотя в логе урона пишет "наносит N единиц Ледяной огонь" как отдельную школу.
Вот полная вырезка истории школы
"Frostfire" as something associated with mages was first mentioned as the name for the Frostfire Regalia set in vanilla WoW. However, the mechanic was not implemented until Wrath of the Lich King, with the introduction of [Frostfire Bolt]. Although the Frostfire school did not exist at that time, Frostfire Bolt's mechanics served as a prototype for the multi-school effect, dealing whichever type of damage the target was most vulnerable to. The school was officially introduced in patch 4.0.1, along with the second Frostfire spell, [Frostfire Orb]. However, Frostfire Orb was later removed in patch 5.0.4.
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Multi-schools were introduced with patch 4.0.1, although [Frostfire Bolt] had served as a prototype of the effects of multi-schools since patch 3.0.2.
То есть школы frostfire еще небыло, но заклинание уже имело эффекты как в добавленных школах позднее.
P.S.: были бы у меня доказательства про интеррапт ффб до каты, был бы еще один пункт