The Definitive Dark Knight Guide

[Xenosan]

But shouldn't the mp you gain from non DA cns be counted as that cns's contribution to damage?

C&S unbuffed rewards half the MP needed for a Dark Arts. C&S has a 60 second cooldown. It'll take 2 C&Ss (1 or 2min) for the MP return to provide a 'free' Dark Arts that you otherwise wouldn't have had access to - and you're sacrificing 700 potency to get it.

Still though - you're a tank, so EHP > DPS if appropriate. If you're in a scenario where you're taking high inc damage and you feel a self-heal is more important than a DPS boost - then yeah obey that priority instead and just vanilla C&S - which will move DA'd SE's availability up 1 syphon combo.

edit: And yeah I agree in AoE/Multi target situations C&S can be better strictly for the MP because it gives a 'free' Dark Passenger with each use.

Passenger is 30s CD, C&S 60s CD. Every other Passenger is free.