To summarize: we must distinguish between the intrinsic nature of these Partzufim on the one hand and their actual functioning on the other. Their intrinsic nature as the root of the Mental Powers in Zeir Anpin remains constant, but their functioning – to spread and actually transfer the Mental Powers to Zeir Anpin – is not constant but depends on men’s deeds. Nevertheless, they function in accordance with their intrinsic nature.
The coupling that channels vitality to the worlds derives from the root of the governmental order (Abba and Imma), which is always in a state of repair. However the purpose of the coupling that produces new Mental Powers in Zeir Anpin – i.e. when Chochmah and Binah, Israel Sabba and Tevunah join together – is that these powers should spread to the lower realms. And since it depends on men’s deeds, it is therefore not constant.