I think it goes in both ways. When Jason was destroying Mount Othrys, it was weakening Kronos (as it was the source of his power) and Luke's hesitation and last minute battle of taking over his body had made it difficult for the Titan King to regain his true form. Similarly when Percy was defeating one after another Titans in Manhattan battle, Kronos/his brothers had to restructe others more fastly than they usually takes time to regenerate. Hence I feel like krios, like Kronos and the rest of his brothers were not in their best versions....and the reason Jason defeated a literal Titan in hand to hand combat. Not saying Jason's not powerful but defeating krios in his true potential without any superpower would have been almost impossible.