I think a 4th order bandpass, eventhough it has a sealed chamber, performs very differently than does a simple sealed system. So its really not relevant. If it was, you'd see alot more people running 4th order BP's in SQ setups, rather than all those sealed ones.
I believe most people's point is this person would have likely achieved just as good of results, if not better, if he'd used half as many subs, but ported them. Im not necessarily saying that's true, there are alot of factors, Im just clarifying what most people here are thinking.