At appeal, the Crown accepted the bill was "manifestly excessive" as it would take him more than 63 years to pay off.
Fannin's lawyer, Richard Keam, argued a figure of just over $5000 was appropriate punishment but Justice Anne Hinton disagreed.
She said the defendant's previous position at such a reputable school meant he was "obviously highly regarded and well qualified".
"I consider he will be able to obtain a well-paying job once his period of home detention concludes, and there would be no reason not to have a job lined up beforehand," Justice Hinton said.
She ordered Fannin to pay $36,400 over the next seven years.
Fannin's fraud spree began when he found out about Jamie Stephen Herdman through Facebook.
The Whakatane 26-year-old was last seen hitch-hiking in a remote area of Australia's Northern Territory in November 2006 and his vehicle was found abandoned by a pub.
Fannin managed to obtain Herdman's birth certificate from the Department of Internal Affairs and used that document, along with fake proof of address, to get a driver's licence in the missing man's name.
From there he successfully applied for credit cards from three banks, which he used for an $8000 spend-up.
Fannin's offending became more brazen when he took driver's licences from two men he taught with at Auckland Grammar and extended his web of fraud.
The father of three is an undischarged bankrupt and is serving his home detention sentence in Whangarei.
