Noc AST is surprisingly very good at Sephy Ex due to the outgoing AoE damage that can be covered with Helios as well as the spike damage that can be covered with A. Benefic. In fact, I'd say Noc AST is better for Phase 3 than SCH purely because of instant shields and Lightspeed for the pillars. Although Deployed Tactics is the strongest AoE mitigation there is...watching Seph's ult do no more than 200 damage gives me healer orgasms when I manage to deploy a Crit Adlo.