What's the reason that U2's concerts don't show on Billboard's Top Concert Chart?? The link to the Top Concert chart is right off the billboard.com main page.
Simple - the promoter is witholding the sales figures until the end of the tour - it happens alot. For instance - the Bette Midler shows in Australia that are topping the list were weeks ago - the figures were officially released at the conclusion of the tour for tax reasons.
You'll see a flood of U2 ones in a few weeks before they head off to Europe - if they decide to release them at all.