In the revised fourth draft of A New Hope in 1976, the description for "Kessel Run" is put as follows:
"It's the ship that made the Kessel run in less than twelve parsecs!"
Ben reacts to Solo's stupid attempt to impress them with obvious misinformation.
So it implies that the puzzling speech of Han Solo is "misinformation" and not truth, and it has nothing to do with the nature of the Kessel Run in any respect. Han means nothing other than impressing Obi-Wan and Luke with pure boasting. Indeed, even in the final version of the script, the parentheses attached to Han's line state that he is "obviously lying."