"This decision was made in accordance with the prosecution guidelines," a spokesperson said in a statement.
But the decision may lead to more answers about the lead-up to Ms Ticehurst's death.
The release of a government report into the 28-year-old childcare worker's interactions with domestic violence services has long been held off until the end of the legal process.
Ms Ticehurst's mother Kate Shaw implored Premier Chris Minns to release the report into her contact with the government's Staying Home Leaving Violence scheme, designed to help victims boost their home security.
"She was my only child, was much loved and is sorely missed by me, her father Tony, her son, her extended family and many friends," Ms Shaw said in a statement after Billings was jailed.
The premier has been contacted for comment.
Justice Natalie Adams set a non-parole period of 20 years, finding Billings murdered his former girlfriend in revenge, "extreme hatred" and retribution for her reporting allegations of sexual assault to police.
Billings, a former mine worker, smashed into Ms Ticehurst's bedroom window at her house in Forbes, central western NSW, before midnight on April 21, 2024, stabbing her 15 times.
The 31-year-old had repeatedly threatened to break into Ms Ticehurst's home and kill her in the months after she ended their on-and-off relationship in December 2023.
Ms Ticehurst reported his abuse to the police in early April 2024, leading to several sexual assault and domestic violence stalking and intimidation charges.
Billings spent one night in police custody, but was freed on bail by a local court registrar a fortnight before the murder as there was no judge on duty on the weekend.
Upon his conditional release, Billings became enraged and obsessed with a belief he had been wrongfully accused of rape and formed a plan to kill her, the court heard.
The Crown did not seek a life sentence for Billings.
But prosecutors argued his level of culpability was "extreme", urging the judge not to apply the legislated 25 per cent discount for his early plea in the local court.
Justice Adams said there was no known case in the state's history where the discount for an early plea had been dispensed with entirely.
The judge found Billings' moral culpability was reduced to his deprived childhood, which led to chronic depression.
She instead granted Billings' a 20 per cent discount, taking seven years off what would have been a 35-year maximum term.
The sentence caused widespread community backlash, including from the premier.
The judge commented on the complexities of sentencing law several times during the proceedings, including pointing out that the 25 per cent discount granted for early pleas is "very large" when applied to long sentences.
Orange MP Philip Donato, who has since been pushing for life sentences for domestic violence murderers, said he was disappointed but not surprised by the decision not to appeal.
"If this wasn't the most objectively serious example of domestic violence murder, then I don't know what is," Mr Donato said on Friday afternoon.
Billings will be 49 when he is eligible for parole.
1800 RESPECT (1800 737 732)
Lifeline 13 11 14
Men's Referral Service 1300 766 491
National Sexual Abuse and Redress Support Service 1800 211 028
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