U.S. CARGO PREFERENCE SQUABBLE CONTINUES The U.S. Agriculture Department said it will begin charging interest tomorrow on the over 12 mln dlrs the Department of Transportation, DOT, owes USDA to pay for its share of the cost of shipping food aid on U.S. vessels. USDA General Sales Manager Melvin Sims told the Senate Appropriations Agriculture Subcommittee his department had billed DOT 12 mln dlrs, and that interest on that amount and an additional charge would begin accruing April 1. USDA's Foreign Agricultural Service Administrator Thomas Kay told Reuters DOT could owe USDA as much as 20 mln dlrs. The two departments are trying to hammer out an accord on how to fund the increasing share of food aid required to be shipped on U.S. flag vessels under a 1985 farm bill provision on cargo preference. Sims said the agencies were near to reaching a memorandum of understanding governing how DOT would pay for its share of the cargo preference costs. Under the 1985 bill, the percentage of food aid shipments carried on U.S. vessels was to increase gradually over three years to 75 pct in 1988 from 50 pct. Although the increased cost was to be funded by DOT, Sims said that department to date has contributed no money.