Defense industry restructuring costs have been less than originally estimated, according to a recent report by the U.S. General Accounting Office - the investigative arm of Congress: $849.3 million through last year rather than the $1.4 billion originally estimated in 1993. The workforce decline over the same period in the restructured companies was also less: 15,000 instead of the estimated 19,000. Commenting on the report, officials of the Aerospace Industries Association noted that savings of $1.93 were realized for every $1 of restruc- turing cost. - J.R.