The point was that different cylinders in those engines run under different conditions. Loads, temps and such are different for each cylinder. Therefore a system that can treat each cylinder as its own unique engine should be able to get better fuel mileage.
Either that or try to make the conditions the same for all cylinders. This is more than just temperatures since the wonky intake manifold and exhaust system are not uniform. Dual port was a step in that direction but, agreed, still far from ideal.
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