He parked his car at a Chambersburg motel, rode a bike to her home, entered the house and attacked her with a stun gun, according to Pennsylvania State Police records.
The jury didn't convict him of aggravated assault in the attack of his wife's sister, Donna Hilton, in the same incident.
Trial Judge John Walker erred in sentencing Benchoff on Dec. 13, 1995, according to a state Superior Court ruling. The court said the burglary and simple assault charges should have been merged in sentencing.
That point made no difference Tuesday as Herman imposed the same four-to-20-year state prison sentence for burglary. Walker had given Benchoff two years probation for the simple assault charge and seven years probation for criminal trespass.
Benchoff expressed his remorse for the attack and psychiatrist Dr. Harvey H. Shapiro said, "he's not a threat to himself or anyone else."
Before sentencing, Benchoff's attorney, Sudhir Patel, asked Herman to lessen Walker's sentence. Patel said a shorter sentence might convince Benchoff to drop an appeal of his conviction.
Herman said he wouldn't bargain with Benchoff.
Although he couldn't sentence him for simple assault, Herman said he considered the circumstances of the crime in imposing the sentence.
"It's disappointing. We were certainly hoping for a time-served sentence," Patel said later. Benchoff has been in jail since the incident.
Patel said the appeal will go forward. Benchoff is alleging ineffective trial counsel and Patel said a hearing will be held later before Herman.
Robin Benchoff and Donna Hilton both testified at the hearing. The original sentence ordered Robert Benchoff not to contact any victims, but Robin Benchoff said her ex-husband called her and sent letters from prison.
Patel said the collect call was accepted by her and lasted 32 minutes. He said there was no proof the letters came from his client.
The burglary sentence for Benchoff is consecutive to a two-to-12-year sentence on two counts of interference with the custody of a child.
Benchoff pleaded guilty to those charges for taking his two children out of state two months prior to the Christmas attack on his wife.
Robin Benchoff and Hilton declined to comment after the sentencing.