Two of the offences involved offending against a woman who woke to find Nixon in the bed touching her. She yelled at him, telling him to leave then went back to sleep. Later in the night, Nixon returned and had sex with her while she was sleeping.
Nixon appealed his conviction and sentence, saying his guilty pleas ought to be set aside and his convictions quashed, the Court of Appeal judgement said.
"He suffers from autistic spectrum disorder (ASD). He says his counsel failed to put forward a tenable defence based on a reasonable belief that the complainants consented to sexual activity," the judgement said.
Nixon argued his ASD led him to misread social cues, and the sentence imposed was manifestly excessive as the judge did not give appropriate credit for his ASD and remorse.
Nixon's claims about misunderstanding whether the victims were consenting to his sexual advances were not supported by the summary of facts he pleaded guilty to.
"The difficult was that the agreed summary of facts, still not challenged on appeal, had most of the complainants specifically telling Mr Nixon that they did not consent."
The court declined the conviction appeal.
On the sentence appeal, Nixon's lawyer argued the judge's five per cent reduction in sentence for Nixon's ASD was not enough.
Experts provided reports saying Nixon was likely to struggle in prison reading the non-verbal and verbal cues in the environment, warning him about who to approach or who to avoid.
"The combination of remorse, rehabilitation and a modest allowance for the specific effects of ASD on Mr Nixon's experience in prison, lead us to conclude that the discount should have been more," the judgement said.
The court allowed the sentence appeal and reduced the prison term, but left the concurrent sentences undisturbed.
