The Latics have sold around 22,000 tickets for the Wembley meeting with Millwall, prompting the FA to make the spare 10,000 available to "neutral" supporters.
"It's not about the numbers," he said. "The numbers need to have a meaning.
"Back in 1995, when I arrived at the football club, we had gates of 2000 people.
"Now we are in the best league in the world, and we are in the semi-final of the best cup competition - for us to take whatever figure it is represents an incredible percentage of the town.
"It's an incredible turnaround of the fans we had 15 years ago, so for us it is a success."