More than 125 Ballou High School juniors, whose scores on a national aptitude exam were invalidated because counselors allowed them too much time to complete their answers, cannot retake it, a spokesman for the agency that adminsters the tests said yesterday.

The students will receive the scores to use for their own information and will be allowed to take a related test to qualify for scholarships, according to the spokesman for the New Jersey-based Educational Testing Service who asked not to be named.

The Preliminary Scholastic Aptitude Test, which 127 Ballou juniors took on Oct. 23, is used as a "warm up" for the subsequent SAT exam and to qualify students as semifinalists in two major scholarship programs that offer funds towards college tuition and expenses.

The SAT is used for college entrance requirements and to qualify students as finalists in the National Merit Scholar and National Achievement Scholar programs, which offer thousands of dollars in assistance, the spokesman said.

Students are usually allowed to use the SAT scores to qualify for the scholarship programs if they were unable to take the PSAT because of illness or other unforeseen circumstances, such as "storms or acts of God," a spokeswoman said.

Also yesterday, D.C. school officials and students complained that Ballou counselors and administrators were "careless" in the way they supervised the tests and the ETS spokesman's report about the circumstances surrounding the incident contradicted an explanation given earlier by Superintendent Floretta McKenzie.

In an interview last Saturday, McKenzie said that Ballou principal Helena Jones told her that the counselors who administered the exam to the students in the school cafeteria, "thought they took too long to explain the answer sheets," and on the following day, gave students additional time to finish the tests.

McKenzie said the counselors made "a bad judgement call" that Jones discovered and reported to superiors and ETS immediately.

However, an ETS spokesman said, "We were alerted by a concerned parent [that the test was mishandled] almost a month after the test was given. The parent said the test was given over two days because the test was disturbed by students coming in for lunch. We called the principal and she said the test was given over two days, but not because it was interrupted by lunch, but had been under-timed by 15 minutes."

Several students who took the exam told a reporter that they were interrupted several times by announcements over the public address system and "clanging" noises emanating from the kitchen.

McKenzie said that her explanation was based on a report given to her by principal Jones. Jones declined to comment.

Tonnia Switzer, 16, said she was not told that her scores were rejected. She said the distractions were "not fair. I want to go to college and major in accounting. I wanted to see how well I scored, so I could know what to improve on before I take the SAT . . . . "