A jury found the man guilty last year on six of 13 charges - two indecent assaults, three of sending indecent messages over Facebook, and one of grooming. He pleaded guilty to sending one set of messages.

The man was found to have indecently assaulted the girl, who was between 11 and 13 during the time, twice while she was at his home.

The Facebook messages were found to have been indecent - some included sexual suggestions, and one was of a photo of his nipple.

In one message back he elicited from the girl a photo of her breasts.

"The offender's conduct on this occasion was predatory and disgraceful. It was a callous, selfish, exploitation of a vulnerable young girl," Justice Steven Rares said in December last year when sentencing the man to nearly five years in jail.

The man was at the time of the offences in 2013 to 2015 between 58 and 60 years old. The court heard he would sometimes partner with the girl in dance classes.

While the man was found guilty of two indecent assaults, the jury had acquitted him of a further six.

In an appeal heard earlier this year, lawyers for the man had argued the jury's verdicts were inconsistent. They said the girl's credibility was crucial, and if the jury did not accept her evidence on some allegations, it could not, consistently, accept it for the others.

On Monday, a full bench of the ACT Court of Appeal rejected that argument. Justices John Burns, David Mossop and Darryl Rangiah said there were circumstances that explained the jury's different verdicts.

This included the way in which the allegations had been drawn from the girl. There were effectively two sets of disclosures. The first two charges came from the first disclosure.

The second set of charges, for which the man was acquitted, came in a second set of disclosures after the first police interview when the girl was speaking with her mother about what had happened.

The court had heard evidence during the trial about the need to be careful when interviewing vulnerable witnesses, and particularly the dangers of asking leading questions - which suggest the answer.

The judges also dismissed an appeal on the sentence.

"Even putting aside the significant age difference between the appellant and the complainant, there remains the fact that the appellant occupied a position of trust with regard to the complainant.

"The appellant was aware of the complainant's troubled background.

"He was a trusted member of a circle of people formed to provide emotional support to the victim. These offences demonstrate a gross breach of trust."

The sentence, of four years and 11 months in prison with a non-parole period of two-years-and-six-months, still stands.

The man is due for release in March 2019.