Tatsua Aiisen said
Mod souls don't really...grow. Your abilities wouldn't increase or change much from when you were initially created.
Considering the knowledge we have about Mod-Souls, much is unknown about that and it is plausible, but then there is the possibility of having them adapt considering they are artificial life, they in sense have to adapt. And those Modified-Souls who don't simply die or last until they are overwhelmed after what their pre-set abilities can do.
(Edit: but I dont know much about Mod-Souls but I know they are intelligent, so what says they cant adapt, or improve their current abilities?)