In its decision the court cited recommendations from experts and noted the original decision did not "reflect potential gains from treatment".
Kiddell had received "very little treatment until recently", and evidence indicated he had already made some gains from recent treatment.
Kiddell, who was born in 1957, has a long list of offences dating back to 1978 when he was convicted of obscene exposure.
In 1986, 1989 and 1990 Kiddell was three times convicted in Australia for wilful exposure.
In 2011 he was convicted in New Zealand for doing an indecent act in a public place.
The Crown alleged he undressed on a hillside by a beach where a teenage girl was swimming and masturbated while looking at her. He fled to Australia before sentencing.
In 2015 he was convicted in Australia of committing an indecent act with a
person under 10 years of age, after exposing himself to a 9-year old girl in a swimming pool and masturbating.
In 2016 he was convicted of indecent communication with a young person after sending photos of himself to what he thought was a 13-year old girl in the Philippines, but turned out to be a police officer.
Kiddell had also described sexual activity he intended to have with her and
claimed to have taught many young girls to have sex.
Police also found 138 images and 14 video files of an objectionable nature on his computer, which included sexual activity between adults and children.
This offending earned him a sentence of two years' imprisonment.
Kiddell's history included other incidents that did not result in convictions, including reportedly being seen masturbating on a hotel balcony in view of schoolchildren in 2000, and in 2013 masturbating in bushes at a beach in view of the complainant.
In reducing the length of the ESO, the Court of Appeal said it was reasonable to assume that so long as Kiddell's risk remained high he would continue to receive and benefit from appropriate treatment.
Kiddell also had some limited "pro-social support".
Should his risk remain high at the end of the five years, it was open to Corrections to apply for an extension, the court said.