AUBURN – A Sabattus man convicted of manslaughter for shooting his father is expected to be back in court next week seeking a shorter sentence than that calculated by the prison that’s holding him.

Scott Poirier, 36, filed a motion in Androscoggin County Superior Court through his attorney asking a judge to correct or reduce the time he will spend in prison.

A judge sentenced Poirier in March to 12 years with all but five years suspended. At Poirier’s sentencing, Justice Joyce Wheeler said Poirier likely would spend roughly two years in prison, after accounting for time he already served and his anticipated good behavior.

A September letter from the Department of Corrections calculated Poirier’s release date as Oct. 29, 2011. But it likely would change, depending on more time off for good behavior, a prison spokeswoman wrote.

Poirier spent 471 days in Androscoggin County Jail awaiting trial. He was released for six weeks following his jury conviction for manslaughter, before being sentenced.

Steven Peterson, Poirier’s attorney, argued in a written motion that Wheeler intended Poirier’s sentence to last roughly two years. By the DOC’s calculation, Poirier would end up spending about 3 years in prison following sentencing, instead of the two years Wheeler mentioned.

“Therefore, the original sentence was influenced by a mistake of fact at the time of sentencing,” Peterson wrote in his motion.

Assistant Attorney General Lisa Marchese, who was the prosecutor during Poirier’s trial, said Friday she would object to Peterson’s motion.

“Our position is Justice Wheeler didn’t intend to sentence Scott Poirier to two years; she intended to sentence him to five years,” Marchese said. That was clear to everyone in the courtroom at the time of sentencing, she said.

Poirier was charged with murder. A jury convicted him of manslaughter in the 2006 shooting death of his father, Roland “Jerry” Poirier. The jury believed the defendant suffered from an abnormal condition of mind at the time of the shooting because he had been a teenage victim of sexual abuse at the hands of his father.

Poirier stood outside his father’s Lewiston home with a hunting rifle while his parents, siblings and other family gathered around a dining table celebrating the elder Poirier’s 65th birthday one rainy November night in 2006.

Poirier fired a shot through the French doors from the patio. It shattered a wine bottle on the table and struck Poirier’s father in the neck. He died at the scene.

Marchese sought a 13-year sentence. Peterson argued for no jail time beyond what Poirier already had served.