Retired general William C. Westmoreland, showing some of the first signs of strain under the third day of questioning by CBS lawyer David Boies, said today that after a "retroactive adjustment" of Vietnam enemy-troop figures that dropped some categories and expanded others in 1967, it was "strictly coincidental" that some enemy totals remained approximately the same.

In his $120 million libel action against CBS, the 70-year-old general has been trying to prove that the network libeled him when a 1982 documentary accused his command of juggling enemy-troop data in 1967 to maintain public support for the war in the crucial period before the Tet Offensive in January 1968.

At one point, Boies, expressing incredulity, asked the general why -- after a revamping of the enemy Order of Battle that removed the communists' "home militia" units and political workers -- the enemy totals for the previous year remained the same.

"General Westmoreland, are you saying that this third quarter 1966 figure . . . just happened to come out at 285,000?" Boies asked.

"That was strictly coincidental," Westmoreland replied.

Boies told reporters outside the courtroom that he is trying to prove that Westmoreland's officers kept enemy-troop figures under 300,000, by coming up with totals first, then adjusting troop data to fit those totals.

The numbers question is a central issue in Westmoreland's libel action over the CBS documentary, "The Uncounted Enemy: A Vietnam Deception." Westmoreland's lawyer Dan Burt is arguing that the broadcast defamed the general not when it said that he tried to hide higher enemy totals from the media and public, but when CBS said he conspired to keep such intelligence from his superiors.

After persistent questioning by Boies about a chart that Westmoreland used to brief Johnson in November 1967, Westmoreland became exasperated.

"I don't know how I'm going to explain this, but you don't understand what you are doing, Mr. Boies," he said. "You don't understand this chart and you won't give me a chance to explain it."

The general then explained how intelligence officials had "retroactively adjusted" the figures to compare them from year to year.

He said three categories of enemy troops were dropped from the official enemy roster in 1967, resulting in a readjustment of the figures for the two preceeding years on the chart. But after the changes, the new total for one period in 1966 was 285,000 enemy troops, compared with the old total of 282,452.

Boies also is trying to establish that at a meeting in February 1966, Westmoreland's military bosses ordered that he should destroy enemy troops as fast as the enemy was capable of deploying them.

On the stand, Westmoreland said that after the meeting, his superiors had offered "guidance" rather than an order on how to wage the ground war in Vietnam. But he acknowledged that the guidelines had not been achieved by the end of 1966. CBS is trying to prove that the general was so concerned about showing progress in the war that he blocked a higher troop estimate that came to him in May 1967.