At some point it was Canon that Lando was the best pilot in the Galaxy. It's piloting skills were given "Stats" in one of the Star Wars roleplaying handbooks, and they were superiors to Han's, and any other pilots. I'm not sure but i think my opening phrase (Lando is the best pilot in the Galaxy) was in it's description. Han Solo was still an Ace, stat wise, superior to Luke for example if you don't factor in the Force (wich can momentarily make Luke or some other Jedis even better than Lando in the game ) , but so were a bunch of others. Lando was considered without equal, didn't brag about it. And that's what is shown in the Death Star 2 race and attack. The dish event is not a mistake by Lando, it's just that the Falcon wouldn't have gone through any other way (so it shows that litteraly at extremely high speed Lando made it go through the smallest crack that the Falcon COULD go through.)
However that version of the Roleplaying is not Canon anymore, i don't know about the current version. (EDIT : from other post I just Saw, it is now Canon that Lando is quite inferior to Han...i'm so sad) But Return of the Jedi still stands.