I wouldn't put too much store by what Han Solo says. A parsec is a measure of distance
, not time. It's like saying 'I made the run from London to Brighton in 55 miles.
Hey if you drove across a couple of fields / backgardens you could maybe shave a couple of miles off that.
Perhaps Han found a "short cut" to Kessel?
Oh God, people are now going to start quoting from the EU and mention the black holes around The Maw / Kessel and how Han did take the "short way" to Kessel.