House Panel Hears Explanation Of How Tax Shelters Help Rich
House Ways and Means Com opens hearings on revision of tax laws; com chmn Al Ullman plans to cover 20 categories of changes within 6 wks; com member Joe D Waggonner Jr objects to timetable; other com members doubt Ullman's timetable could be met; staff members explain how tax shelters work; cite 3 specific cases: doctor with income of $105,000 legally paid no income tax; stockbroker with income of $181,000 paid $1,000 tax, and business exec with income of $448,000 paid $1,200 tax; individuals not identified; staff members describe practice of 'leverage' whereby borrowed money is turned into big tax deduction; Ullman says tax laws should be changed to make sure tax code does not provide main incentive for investment; Repr William M Ketchum says risk capital would not be available without tax shelters; Repr William A Steiger says police and firemen in his dist who invested in duplex houses are concerned over what will happen to them if com 'goes after big boys' (M)