When I play AST, I have a preference for NoctSect (Through ARR and HW I mained SCH, it's a learned behaviour to think about shields over regens). BUT, if the other healer is a SCH, I'll go DiSect, if the other healer is a NoctAst, I'll go DiSect. It's a preference, but I will happily be flexible about it. Because by being flexible, I can adapt to the situation, which I find more important.