TALLAHASSEE — For years, county officials say, they've had to shoulder too much of the cost of dealing with young offenders. In recent years, they say, the state has erroneously billed them $140 million for juvenile justice costs, sparking legal action.

Now, with the annual legislative session drawing to a close, the costs are at the center of the latest budget dispute.

Lawmakers have proposed a new funding formula that counties agree would avoid future billing disputes. But only the House proposal, HB 5305, also reimburses counties for previous overpayments through small annual installments.

Counties — especially large urban centers that are bearing the brunt of costs — are hoping the Senate will embrace the House plan during budget negotiations that begin when lawmakers return Monday.

"When the state overbills us over $14 million (over several years), we need to be compensated," said Miami-Dade County Commissioner Sally Heyman.

The funding dispute affects 38 counties that since 2004 have been expected to help pay a portion of the costs of incarcerating youths before they are sentenced. The 29 more rural counties are considered "fiscally constrained" and are exempt from the requirement.

In the past decade, 19 counties have filed legal challenges against the Department of Juvenile Justice over billing issues. They argued that the state arbitrarily shifted up to 75 percent of detention costs to counties in some years.

The House and Senate hope to end that litigation through a new billing formula that requires counties to pay 50 percent of youth detention costs. But the two chambers disagree on whether counties should be credited for the extra money they paid in previous years.

Sen. Rob Bradley, R-Fleming Island, is chairman of the Senate's criminal justice budget committee. He said his proposal, SB 1532, factored in past overpayments when he came up with the 50-50 formula. "Our percentage split is more generous than perhaps it would be otherwise because we acknowledge that the counties have this argument that they believe they are owed back payments," Bradley said.

If the House and the Senate can't iron out a compromise during budget deliberations, Gov. Rick Scott's billing plan would likely be implemented. It would require counties to cover 57 percent of juvenile detention costs and receive no back payments.

The Florida Association of Counties has labeled it the worst of the three plans. For instance, Hillsborough would owe $4.3 million and Pinellas would owe $3.4 million next year under Scott's plan, significantly more than under either the House or Senate plan.

"It remains to be seen if we're able to resolve this matter in the two weeks that are left in this session," Bradley said.

Rep. Darryl Rouson of St. Petersburg, the ranking Democrat on the House's Justice Appropriations Subcommittee, believes the best solution includes reimbursing counties for overpayment.

"It's been a thorny issue," he said. "Counties have felt for some time that they are right and should have not been overbilled. The Department of Juvenile Justice has dealt with budget constraints and felt that it was right."

Contact Tia Mitchell at (850) 224-7263 or tmitchell@tampabay.com.