A district court still must rule on a case sent back last week by the Iowa Supreme Court that struck down a tax differential between casinos located at racetracks and those on riverboats. Dubuque Greyhound Park manager Bruce Wentworth says the track’s been told to begin paying the new lower 20-percent tax rate. He says the district court will have to figure out what to do with money the tracks paid in that was over the 20-percent rate, in Dubuque’s case a total of 11-point-six-million dollars, and beyond that, he says the court can leave future changes up to lawmakers. Wentworth says the Dubuque Racing Association tried for years to get those lawmakers to equalize the tax, but never asked them to raise the tax on riverboats.If the state refunds the tax overpayment to racetrack casinos, it would cost the treasury almost 38-million dollars. That’s why Wentworth worries all the casinos could be defending themselves against an across-the-board tax increase. The manager of the racetrack casino is not worried about cutting into the state’s tax revenues.He says last year the casino paid more than eleven million dollars to the state and now it’ll be able to keep four million dollars more in the community.