A recent change to Florida law is doing something lawmakers say they never intended: allowing school districts to skirt the toughest rules of the state's class-size amendment.

The new law lets districts do something voters rejected twice — calculate class size using schoolwide averages rather than classroom counts. They simply must designate campuses as "public schools of choice" to qualify.

And that's what Pasco County has done — for its whole district.

"Ninety five percent of our schools are schools of choice, because we have kids opting in," spokeswoman Linda Cobbe said, referring to a plan that lets students attend schools they aren't zoned for, if space is available.

This year, Pasco schools had 2,274 students transfer in from another campus. It also deemed 23 schools "frozen" to choice because they had no available space. All were put forth as schools of choice.

"We feel confident they meet the definition in law," Cobbe said.

Backers of the 2002 amendment to reduce class sizes aren't so sure.

"It seems to me there are serious constitutional questions raised by any statute which purports to relieve the school districts from meeting the targeted numbers that are expressed in the Constitution," Ron Meyer, a lawyer for the Florida Education Association, said Friday.

Pasco district leaders didn't think they would meet the class-size requirements this year. In fact, they budgeted nearly $214,000 for the fines they expected to pay for falling short.

They changed their tune after learning about the new law in an Oct. 4 Department of Education memo. They used it to help determine that all schools met the limits in the state's October student count.

Districts were required to document their "schools of choice" by Oct. 11. Florida Department of Education officials said they did not yet know how many districts used the same methodology that Pasco employed.

Pinellas, Hillsborough and Hernando officials said they used classroom counts.

Senate Education Committee Chairman John Legg, a Pasco County Republican, said his office has received reports of districts using what he considered an unintended consequence of the spring session.

The concept initially arose as part of Sen. Bill Montford's proposal to let school districts create their own charter schools. The rationale was that districts would have an easier time implementing the new program without class-size restrictions, which already are at the schoolwide average for charter schools.

"This was not an effort … to undo the class-size amendment by coming in the back door," said Montford, who also heads the state superintendents association. "However, at the same time, what we have to do is give school districts the flexibility to do what is best for their students."

Portions of Montford's bill were merged into a different proposal that made it into law.

Legg contended that allowing districts to deem all their campuses "schools of choice" to get around the amendment, which most superintendents fought to scale back, was not the point. He suggested a legislative tweak could come in the 2014 session.

"If school districts are following the letter of the law, they're following the letter of the law," Legg said. "We want to provide the flexibility they requested, not the loophole that was granted."

The FEA argued that if the Legislature had intended to give districts blanket permission to slip past the class-size rules, it had its chance and passed by killing other related bills.

"The people of Florida enacted a constitutional amendment," Meyer said. "Instead of figuring out how to do that, we tend to spend an awful lot of energy figuring out how to get around it."

Jeffrey S. Solochek can be reached at jsolochek@tampabay.com or on Twitter @jeffsolochek.