This past case concerned an appeal against sentence by a person who had pleaded guilty to attempting to obtain possession of a commercial quantity of narcotic goods (MDMA, or ecstasy), a federal drug offence. The sentence imposed had contained a mathematical error which needed correction. The Learned Sentencing Judge had indicated an intent to reduce the sentence imposed by 25% to make allowance for the sentencing discount provided for an early plea of guilty; unfortunately His Honour accidentally reduced the sentence by one year less than the full 25% discount.
See http://www.austlii.edu.au/au/cases/wa/WASCA/2002/357.html.