I couldn't agree more with this. When running VoD elite (which is about as tough at 20 as VoD hard was at 16), my approach is simple - aim have at least 90% SP left when Suulo hits 40% and flies up for the trap/trash phase, at least 60% left when the second Orthons spawn, and at least 20% when the suicide bomber firebats spawn.
That way, even if the group was careless enough to belt Suulo from 40% to 20% hardly killing any of the trash (and this happens), you have the SP to just brute force heal through it all, and to drop a bladebarrier to get most of the orthons and trash aggroed onto you so you can kite them while healing the group.