LOS ANGELES (AP) -- Hundreds of inmates aren't getting the early releases they earned through good behavior and working in prison, costing the state millions in housing costs and legal settlements, according to a report published Sunday.

Offenders were set to remain in prison longer than they deserved in more than half of the 679 inmate cases sampled last year by state investigators, according to records obtained by the Los Angeles Times.

Fifty-nine of those prisoners had already overstayed and were released after serving a total of 20 years too many, an average of four months each.

"They just did what they wanted to do at the Department of Corrections," said Nicholas Shearin, 38, of Hawthorne, who received less than a third of the good-behavior credit he was due and was released from prison eight months later than he should have been.

The state paid $468,280 in legal settlements between 2000 and 2004 and to prisoners who weren't released on time, according to a 2006 report published by California State University, Sacramento.

State researchers also projected that for the 354 inmate cases reviewed last year, it would have saved $2.3 million in housing costs if all had been released on time.

Failing to correct the errors could cost the state more than $110 million more over the next 15 years, researchers said.

Analysts who compute sentences for state prisoners said insufficient staffing and outdated computers are to blame for the late releases.

Karen DeVoll, an analyst at Sierra Conservation Center, said she has decades-old computer systems that cannot calculate current sentencing formulas.

She and her colleagues do most of their work with pen, paper, calculators and file folders jammed with inmates' papers, she said.

Scott Kernan, the corrections department's chief deputy secretary for adult operations, said the prisons plan to add 85 new analysts so that all questionable release dates can be corrected by September.

But analysts will also have to review tens of thousands of additional prisoner records if legislators approve Gov. Arnold Schwarzenegger's plan to release some prisoners early to help close a $14.5-billion budget gap, and that could mean new delays.

State Senate Majority Leader Gloria Romero, who chairs the Senate's public safety committee, said the Department of Corrections was violating inmates' right to a timely release.

She criticized the prison agency's "arrogance in the face of the law to simply say that these people's lives don't matter, but they can just lock them away and essentially throw away the key."

But Kernan defended the department.

"Our staff struggle every day and do a wonderful job in calculating these cases and prioritizing the workload and getting these guys out," he said. "We're doing as much as we possibly can with the existing resources we have."

(Feb. 18, 2008)