That's my original source for it too. But I think I've seen something more recently that showed the script reference. From the Wookieepedia page on the Kessel Run: Which is ambiguous, admittedly; it could either mean that he isn't using "parsecs" correctly or that they know it's impossible for the ship to perform as well as he claims. So it's inconclusive. It goes on to say: So in this case, it would seem that it's Lucas's claim that it really does make sense that's the revisionist explanation, and the original intention was that it didn't make sense (in one way or another).