A disputed facts hearing found the Crown could not establish there was a sexual relationship between the two in the period before that.
Ms Woodcock said the girl didn't consider herself a victim, but the acts were deliberate and occurred on multiple instances.
Barron's pre-sentence report showed he expressed no remorse and had a continuing sense of entitlement.
Barron's counsel, Stephen Ross, said the frequency of the cases was challenged and evidence established intercourse over two months, which was always accepted by Barron. Any more than that was speculation.
There was no abuse, manipulation, grooming or evidence of impact on the girl that was able to be presented to the court.
A breach of trust was implicit given she was under 16, but he wasn't a serial offender, he was considered at a moderate to high risk of reoffending, but didn't have any history and the particular circumstances that lead to the relationship wouldn't occur again, Mr Ross said.
Judge Cameron said Barron had a criminal history spanning 1996-2011, with various convictions for drink driving, dishonesty, drugs and violence, but not sexual offences.
There was no victim impact statement and he understood the girl involved wouldn't supply one.
It was an aggravating feature that the offending wasn't spontaneous, and occurred on several occasions in a two-month period. He pleaded guilty, but not at the earliest opportunity.