He had sought an adjournment but the tribunal opposed that, deciding to hear formal evidence in his absence so that members had ``all the facts''.
Stevens today said he did not know the hearing had gone ahead and had not been notified of its decision.
"I thought they would have told me, even as a matter of courtesy,'' he told APNZ.
"I'm speechless more than anything else, because normally you would actually expect to hear.''
Stevens said he had spoken to his lawyer today and they had been waiting to hear from the tribunal whether an adjournment had been granted.
"We asked for the hearing to be deferred so that we could prepare and we are waiting to hear a response about the meeting being deferred, so that's why I was very surprised.''
Stevens said the adjournment had been sought so mitigating factors could be raised.
"But obviously they've gone ahead and made their decision anyway.''
Told about the order to pay costs, Stevens said: "Isn't that charming. Well thank you for telling me that, it would have been nice for them to have told me.''
Stevens' lawyer, Andrew Henderson, could not be reached for comment.
Previously chairman of Wellington Free Ambulance and member of the Victoria University Council, Stevens' convictions resulted from creating false invoices to obtain tens of thousands of dollars over five years.
The court was told he filed fraudulent income tax and GST returns on behalf of his tax agency. They included claims for fictitious expenses which had the effect of reducing the tax liability of his clients, who paid an invoice for the false expenses and received the bulk of repayments. Stevens kept the difference.
Total fictitious claims were about $2.1 million, with a loss to IRD of just over $821,000. Stevens got about $60,000.
Judge Denys Barry ordered him to serve his sentence at his $4.8m Kaiwharawhara property in Wellington and to repay clients $121,851 from the sale of the mansion by early May next year.
Stevens hit the headlines again in February this year when an invitation to a "convicts and tarts'' birthday bash surfaced.
The News of the World-style invite said a big turnout was expected for "well known bete noire Shaan Stevens' 50th birthday celebrations'' at his gated community "hideaway.''
"Starred as the must get to event for 2012,'' it continued.
Following inquiries from APNZ, Stevens said he had cancelled the party. The Corrections Department had not been aware of the event until Stevens contacted his parole officer to say he had called off the event.