I'm trying to get a pattern here.
In the K&N site I got this answer:
An engine can only draw in a certain volume of air depending on the engine's size (measured by such things as bore, stroke and number of cylinders). Vehicles are designed to accommodate large changes in air pressure so they can operate at sea level or at an altitude of 14,000 feet.
Engine computers adjust the amount of fuel required as a result of changes in air pressure (density).
Air filter restriction when the filter is new and especially as the filter loads with dust will result in lower air pressure and availability similar to being at a high elevation. High-flow air filters that were invented by K&N were designed to reduce the work necessary to pull air through the filter and to increase air pressure. Increased air pressure is one of the key elements in producing more power.
This is a graphic from one of Forchetto's great posts
What I'm getting from the graphs is that at high rpm the power and torque remains the same regardless air port size.
Performance does not increase in proportion to Air flow provided from bigger air port.
Hummm... need to go deeper...