The Department of Education, which said this week that it is adding a 10% bonus to the grades of students in Advanced Placement courses, said yesterday that it is using a new $700,000 federal grant to encourage students who wouldn’t ordinarily take the tough classes to try them.

Meanwhile, in the aftermath of an about-face by administration officials on imposing the AP grade bonuses retroactively, parents said they want to know more about the policy before they advise their children, and politicians said the department should be careful not to offer advanced courses to unprepared students.

The New York Sun first reported this week that the education department had decided to grant 10% bonuses to the grades that students received in AP courses. At first, the change was retroactive. That led the department to have technicians quietly change the grades of thousands of students at public high schools, along with the class rankings of tens of thousands of students.

On Tuesday, a deputy mayor, Dennis Walcott, said the new weighting system would be in force only in the future, presumably meaning the grades and class ranks were being changed back. Yesterday, a department spokeswoman told the Sun about the federal funds to boost AP enrollment.

“The Department of Education is working on increasing the number of AP options for students through participating in a U.S. Department of Education AP Incentive Grant,” the spokeswoman, Kelly Devers, said. “We want to grow more opportunities for students in a way that makes sense for all of our schools.”

The one-year grant will be spent on college-preparatory classes for seventh-, eighth-, and ninth-graders. It will also be used to encourage students who scored well on the PSAT tests to take AP courses.

Ms. Devers said the department’s decision to apply the grade bonus was not related to the federal grant.

Currently, 20,402 city students are enrolled in AP classes. The college level classes are offered at only 151 of the city’s 316 high schools. Ms. Devers said the city is striving to boost those numbers.

“We’re working with high schools to see how to increase the number of offerings consistent with the unique programming and staffing needs of each school,” Ms. Devers said.

The chairwoman of the City Council’s Committee on Education, Eva Moskowitz, said enticing more students to take the most rigorous classes seems like a good idea. But she said she’s “skeptical that motivation is the central problem.”

At the city’s highly selective schools, Ms. Moskowitz – who herself is an alumna of Stuyvesant High School – there is a lack of motivation. At more run-of-the-mill high schools, she said, “The problem is less motivation than preparation.”

She said most city high school students need good instruction so they can master basic concepts, rather than college-level coursework.

The president of the principals’ union, Jill Levy, said she’s unclear what the new policy actually is because she still hasn’t seen it in writing, even though it was rolled out at the end of October.

But she said she fears that an already competitive school such as Bronx Science “will become a school of only AP courses” now that the students who take them will get 10% bonuses tacked onto their grades.

Parents said they were glad that the program was no longer being implemented retroactively.

“Any time when you implement a policy, it’s just good policy that you say “This is the policy,'” the co-president of Stuyvesant’s parent association, Linda Lam, said. “People should have the choice to decide to take the AP or not to take the AP. It should not be applied retroactively.”

Ms. Lam said getting into AP courses at Stuyvesant is already competitive and she said the new policy might make it even worse.