Even then, it is theoretical. They take the highest sustained benchmark numbers.
It could have lasted seconds or whatever, no one really knows.
Sustainable transfer rates will always be slower than that.
It's like the Minimum vs. Recommended Requirements of a game.
Min = What it takes to get the game to show a picture and make some movement. Not indicating how much movement.
Recommended = Could be playable for some, but that's about it, and usually at lowest to maybe medium settings. And even that depends on the system. It's playable, but not optimal.
Just an analogy.