The proposed "safety net" that would prevent a school's A-to-F grade from dropping more than one letter grade in a year amounts to "grade inflation" and should not be adopted, according to Jeb Bush's education foundation.

In a letter sent to members of the State Board of Education on Monday, Bush's foundation urged board members not to continue in 2013 the rule that prevented 2012 grades from being any lower than one letter grade from a school's 2011 mark.

"If a school earns a D, but receives a C, who is helped by this grade inflation?" wrote Patricia Levesque, executive director of the Foundation for Florida's Future, in a letter to the State Board. "It certainly won't be the students because the districts will be under less pressure to director resources and assistance to those who need it."

Education Commissioner Tony Bennett said in a letter Friday that he would recommend the board continue the "safety net" -- preventing grades from dropping more than one letter this year.  The board is to vote on the issue Tuesday.

He said he made the recommendation after hearing from an advisory panel he appointed. Superintendents on that panel said they worried so many changes to the grading formula -- approved last year and fully in effect this year -- would lower grades even if students did better on some state tests.

Bennett said continuing that rule would limit changes to Florida's school accountability system in its run up to bigger changes coming in the 2014-15 school year. That is when the state is to implement new academic standards in language arts and math and new standardized tests in those subjects. Those new tests, in turn, will prompt changes to the A-to-F grading formula.

In her letter, Levesque said she understood that view, even if she disagreed.

"Commissioner Bennett is correct when he says a smooth transition to Common Core is the priority. If he believes this helps get us there, we respect his judgment.," she wrote.

So if board members do vote to continue the rule, she wrote, they should not to allow it to continue beyond this year.

 The State Board is to consider the issue at a 10 a.m. telephone meeting Tuesday.