At his sentencing Justice Geoffrey Venning said he was a principal wholesaler with responsibilities for receiving and delivering MDMA and taking payment.
Frewer sought to have his sentence reduced through the Court of Appeal, which partially upheld his application.
His lawyer Peter Kaye argued that the initial starting point Justice Venning used in his sentencing exercise was too high when compared with similar cases.
He also said not enough discount was given for Frewer's guilty pleas and Justice Venning should not have imposed a minimum period of imprisonment.
The Court of Appeal rejected all these submissions, but gave Frewer a two-month reduction in his sentence because it was not clear whether Justice Venning had taken into account he had spent about a year on extremely restrictive electronically-monitored (EM) bail before being sentenced.
"Given the lack of certainty as to whether an allowance for time on EM bail was in fact given, we need to ensure that the appellant is not disadvantaged. We therefore consider it appropriate to make an additional allowance to take account of the possibility that no specific allowance was in fact made," the Court of Appeal decision said.
A new sentence of eight years and seven months imprisonment was imposed with a reduced minimum non-parole period of four years and two months.