The difference here is simple. The 2JR Cowl Induction, works in a low pressure area.. as the car is driven the temps decline to ambient. The inverse is true of nearly every other intake that resides behind the radiator. They start off cool/ambient and build in heat as the car is driven, fans come on, etc.
Think of it like this.. when your car sits, the interior heats up beyond ambient. As you get in, open the windows and drive, the temps reach ambient. Same goes for the 2J intake. Once the cowl reaches ambient, it will stay there.