Permission to dun the Feds is attracting interest on Capitol Hill because of the Administration's announcement that it will begin using private collection agencies to reduce its accounts receivable. In both houses of Congress, a number of names have been added to the sponsorship of acts that would permit businesses to charge interest on federal agency bills that remain unpaid after 30 days. One sponsor, Sen. Lowell Weicker (R-Conn.), cites the case of a small business that was owed $1.5 million by the government, all of it more than 30 days past due, and was forced to borrow $500,000 at 20% interest to meet its payroll. A 1978 General Accounting Office study confirmed that about one-third of all federal procurement debts are paid late.