residential? LOL. I assume he meant reservoir. Unless I am wrong...the stack in there is only slowing down/controlling movement of oil that is displaced.How high does the grass grow?
Flutter is like a directional bleed. Flutter and bleed combined in a normal coilover would make for a sloppy ride. Maybe having the second piston effects low speed damping so it needs it?
Stack in residential is for high speed and cavitation.