At today's hearing the public gallery was packed with supporters of the two defendants.
The SFO laid the charges in July 2012 after an investigation alleged that between May 4, 2005 and October 5, 2008 the two men deliberately under-reported the quantity of gas supplied to its retail customers.
E-Gas under-reported its gas consumption to the tune of about $8.74 million, and penalties were avoided to the figure of about $8.67m.
In his written decision, Judge Davidson said over the three and a half year period, the company under-reported its gas use by nearly 950,000 gigajoules - about 12 per cent less than it should have reported.
That resulted in "substantial financial benefits for E-Gas", which must have improved the company's solvency, he said.
The Crown's case was that both the accused deliberately under-reported the monthly gas allocation and avoided substantial charges and penalties.
Crown lawyer John Upton QC said the amount of money avoided was about $17.1m.
However, the defence said this figure was between $4.5m and $9.7m.
As well as avoiding insolvency, Mr Upton said the extra cash available to the company allowed Hunt and Rosenberg to continue to draw a salary and other entitlements.
The under-reporting remained largely undetected until gas industry audits from 2009 onwards, Mr Upton said.
Both Rosenberg and Hunt denied they were dishonest, and each genuinely believed the monthly allocation could be under-reported.
Rosenberg's lawyer Richard Laurenson said his client said it was a "deliberate management strategy", which started in 2005 in consultation with Hunt and others.
Hunt's lawyer Kevin Preston said his client denied being part of a deliberate strategy and it was much later that he was aware of the level of under-reporting, but was assured it was justified.
Judge Davidson ordered pre-sentence and reparation reports for the pair.
He told them that while the pre-sentence report covered the feasibility of home detention, they were to be "under no illusion" that a prison term was possible.
The charges carry a maximum sentence of seven years' imprisonment.
Rosenberg and Hunt were remanded on bail until sentencing next month.