Clark County District Judge Jackie Glass on Thursday said Titus should have been aware that she had the discretion to sentence him to more than 17 years after Titus pleaded guilty to second-degree murder for his role in the killing.
In August, Glass sentenced Titus to 21 to 55 years in prison.
Defense lawyer Marc Saggese said he recommended Titus enter the guilty plea because he believed Glass agreed to sentence his client to 17 years. Saggese has said he was "blindsided" by the stiffer sentence, which pushed back Titus' parole eligibility by four years.
Judges are not bound at sentencing by plea agreements.
Titus, 43, and his wife, Kelly Ryan, were accused of beating and killing their 28-year-old personal assistant, Melissa James, in December 2005. They left her body in a torched car.
Ryan pleaded guilty to arson and battery with a deadly weapon causing substantial bodily harm. Glass sentenced her to six to 26 years in prison with parole possible after six years.
Titus said at his sentencing hearing that he accidentally killed James during a drug-fueled fight.
Titus is a 1996 bodybuilding champion and Mr. Olympia competitor. Ryan is a past Fitness America and Fitness International winner.