Copies of the official master score sheet for the Sugar Ray Leonard-Roberto Duran championship bout released today show two changes made in the voting by one of the three judges, Angelo Potelli of Italy.

Potelli's 10th-round vote for Duran was alterted with a zero written over a nine and a one added in front to make it a 10. His overall point total of 147 was superimposed by a slash and another total of 148 written below it.

Originally, the following scores were announced: judge Raymond Baydelrou of France, 146-144, favoring Duran; judge Harry Gibbs of England, 145-144, favoring Duran, and judge Potelli, 147-147, a draw. Referee Carlos Padilla of Las Vegas had no vote.

About an hour after the decision was announced as favoring Duran by a majority decision, it then was announced by Bob Lee, vice president of the World Boxing Council, that a mistake had been made in the addition of Potelli's round scores and that the total should have been 148-147, favoring Duran -- making it a unanimous verdict.

Thus, Leonard lost his welterweight crown by an aggregate of four points instead of three.

Jose Sulaiman, president of the WBC, did not appear at a news conference here today. He was reported enroute to a fight in Las Vegas.

At 4 a.m. this morning, Sulaiman was asked if possible manipulating by the judges after the first scoring was announced could have occurred to make it a unanimous decision.

"It's very sad that assumptions are made on things like that," he said.

"None of the judges had the wrong figures on their cards they handed to Bob Lee. It was his (Lee's) mistake, and his mistake alone. He is (also) the executive secretary of the New Jersey State Athletic Commission. It was a total error of addition. I cannot repeat myself anymore."

The changes in Potelli's figures on the "master score board" were made by Lee. The Washington Post obtained a copy of Potelli's original voting cared for the 10th round. It showed no changes. He scored the round 10 for Duran, 10 for Leonard.

This was the scoring procedure: Cards were distributed to the three officials to be filled out and signed and collected by Lee after every round. Lee's function was to add up the figures on the cards at the end of the fight. Lee said Friday night that in adding up the columns, he originally marked down a nine by Potelli for Duran in the 10th round.

Lee left Montreal this morning, but Eduardo Oreste Lamazan, executive secretary of the WBC, said that Lee discovered his own mistake when he rechecked the voting totals -- after the majority decision had been announced.

Lee then went to the press room at Olympic Stadium and announced his mistake.

Potelli was reported on his way back to Italy today, and unavailable for comment.

Had Leonard managed to garner a few more points on one of the other official's cards, he conceivable could have earned a draw and retained his title.For an hour.

It was a close fight and the officials reflected it by voting an aggregate of 19 rounds even -- Potelli 10, Baydelrou five and Gibbs four. All three had the seventh, ninth and 11th rounds even.

More forthright convictions by the judges easily might have changed the outcome, particularly since a champion usually is given the doubt before the title is taken away. There were no knockdowns and neither boxer ever was in serious trouble.

Ray Arcel, Duran's trainer, acknowledged in response to a question about who won the 15th round, "It was questionable," he said, "I don't lie to my friends. I told Roberto, 'Be sure and try to win the 15th; the last round is very important.' He tried to clown. That takes polish off a boxer's image."

Arcel was referring to Duran registering a mocking smile as if a big punch by Leonard in the 15th round didn't hurt him, and then getting up and on toes and theatrically jabbing for the first time, as if to indicate he was in full command and still energetic.

"I didn't think the fight was that close," Arcel added. "I thought Duran won nine rounds. But we were in the lion's den with that referee (Padilla). I told him (Padilla), 'Don't destroy the fight; the whole world is watching. Let them fight.'

"I don't think any round should be scored even; it gives a fellow (judge) an 'out.' If a man scores 10 rounds even, there's something wrong somewhere."

Freddie Brown, assistant to Arcel, disclosed, "We got word that Leonard was going to try to fight instead of box. He tried to jab and run, but it did him no good. He had no choice about fighting. Roberto cut off the ring on him."

Arcel questioned Leonard's tactics. "All he had to do was try to outbox us," he said. "Move and box. You don't try to change your style to impress an audience, and that's what he did. One man he should listen to is Angelo (Dundee, Leonard's chief second). I doubt that he does; he wants to be like Muhammad Ali."

Could the loss break Leonard's spirit?

"Only Ray knows. He may fool the world, but not himself. If he figures, 'I've got millions now' and loses his incentive, he may as well stop now. He won't improve if he wants to be King Supreme. He will have to study and practice now.

"Roberto has determination. I told him to try to win the first five or six rounds. My fighter was going to try to make Leonard discouraged, hurt him and crowd him. When he hit Leonard in the first round with a hard shot to the liver, I said, 'Boy, that's the one.' That made Leonard think, 'I better watch myself . . . . what's going on?'

"We knew we had to keep him on the ropes. We told Roberto, 'Hit him on the arms too, (as well as in the face and body. Just keep on top of him.' After the first five rounds, it looked like Ray might not make it (to a decision).

"Roberto was motivated by a long hatred, from when Ray said at the signing ceremony, 'I'll not only beat Duran, I'll kill him.' That had been eating at Roberto."