Mr Robb and Wrightsons were ordered to pay $1.101 million in damages to the Stevensons - the difference between the sale price (less commission) and the market value.
The issue arose after the Stevensons chose to sell their orchard in October 2012 and signed with Wrightsons, of which Mr Robb was a listed agent.
Mr Robb rang several people in the kiwifruit industry to advise them of the sale, including the eventual buyer, Paul Jones, who was associated with DMS packhouse. Mr Jones was authorised by his business partners to offer $3.6 million up to a maximum of $4 million and a meeting was arranged.
However, during this time Mr Robb was contacted by another interested party - Craig Lemon, associated with MPAC, a rival packhouse to DMS. Despite ongoing inquiries from Mr Lemon for the sale, Mr Robb "skated" over any mention of Mr Lemon to the brothers - who were aware of Mr Lemon's role in the packhouse industry.
Justice Woolford said if the Stevensons had been made aware of Mr Lemon's interest, it was unlikely they would have sold to Mr Jones for $3.8 million.
The Stevenson brothers lodged the appeal with the Real Estate Agents Disciplinary Tribunal in an attempt to have the second part of the ruling upgraded to misconduct rather than unsatisfactory conduct.
Their lawyer submitted that, there was no difference in Mr Robb's treatment of the potential buyer or the vendors and "if Mr Robb's conduct was not considered sufficient to found a charge of msconduct, it was hard to see what might".
The lawyer acting on behalf of the Real Estate Agents Authority said his conduct was on the cusp of the range between misconduct and unsatisfactory conduct.
The Real Estate Agents Disciplinary Tribunal ordered the matter to be sent back to the Complaints Assessment Committee for reconsideration of the second charge.