Money was well spent, says former chief
Michael McLoone, who was the Donegal county manager when the work was commissioned, defended the project.
He said the work done in Donegal could go on to save taxpayers millions throughout the public sector.
"In relation to the tendering process, I have made it clear that there was no one else available at that time to do this sort of work," said Mr McLoone, who now sits on the Board of Enterprise Ireland.
"I believe this was a substantial and very beneficial body of work. These sort of programmes and systems are widely used in the private sector and can be used in the public sector.
"I look forward to seeing the results of the evaluation report when it is produced."
Asked if he believed the system was good value for money, he said: "I believe that €3m to €4m will be money well spent if this system goes on to be used in a public sector generally, which the Irish State believes should be more cost-effective."
He added: "I do not believe these consultants were paid more than consultants elsewhere in the public sector; in fact, some fees were considerably less."
The council had claimed a reduction in staff at the council by 100 in 2009 was a result of the new work practices recommended by One Sigma.
This claim was roundly dismissed by the auditor.
He said the redundancies were as a result of a Department of Environment directive and the council claim was "without foundation".