because in Defrost mode, it's assumed you want to clear the windows as fast as possible, no?

Mods: EV mod, VVT-i emblem, sport pedals, OEM cargo mat, JDM Prius interior footwell lighting, Sylvania Silverstars 9003ST, DICE iPod kit, OEM all-weather mats, TomTom ONE v2, LED licence plate lights.