An article yesterday incorrectly reported when Detroit Pistons all-star Grant Hill will be a free agent. It will be after the 1999-2000 season. In a chart yesterday on commercial fishing, the amounts were incorrect for some fisheries. Here are the correct amounts, in millions of tons. Kept: crab, 1.22; jack, mullet and saurie, 10.28; cod, hake and haddock, 14.08. Discarded: shad, .02. Performances of Monteverdi's "Vespers" by the Folger Consort will be held at 8 p.m. today and at 7:30 p.m. Saturday at Washington National Cathedral. The time of the Saturday performance was incorrect in the calendar of events in yesterday's District Weekly, and the box office phone number, 202-544-7077, was omitted. The Literacy Council of Montgomery County is located in the Wheaton Library, 11701 Georgia Ave., Wheaton, Md. The name of the town was incorrect in the Volunteers column of yesterday's Montgomery Weekly. A headline in Wednesday's Business section incorrectly characterized the effect of a dispute between Crown Central Petroleum Corp. and the Oil, Chemical & Atomic Workers International Union. Crown's contract with Norwegian oil supplier Statoil has nearly two more years to run, although Statoil has said it will not renew it until Crown resumes normal relations with locked-out union workers. A photo caption in yesterday's Business section incorrectly implied that Amtrak's new high-speed trains are already in service. Also, the caption should have noted that the photo was a computer-generated likeness based on early design plans. An article in the Business section on Nov. 11 last year misidentified the company that created the name Viagra. The name was developed by Wood Worldwide Inc., a New York consulting firm that specializes in brand identities for products.