If they win in the Supreme Court, they will target almost 450 other RAM investors who got paid out more than $80 million from the business.
If the situation remains as it is today, they will only try to recover $40.1 million of "fictitious profits" from about 250 investors in the fraudulent business.
Any money clawed back will then be available for creditors of RAM, who were owed about $115 million when RAM failed.
The liquidators so far received back $4.5 million after settling with 16 investors.
Described last year by a judge as an "innocent investor", McIntosh borrowed $500,000 from Westpac to put into the fraudster's business in 2007.
His investment had purportedly grown to $954,000 when he closed his portfolio four and a half years later and the liquidators of RAM's since-collapsed business went to the High Court at Wellington last March to recover the funds.
While the High Court ruled McIntosh had a defence to the claim for the $500,000 original investment, the Wellingtonian was last year ordered to pay back the $454,000 of "fictitious profits".
McIntosh appealed those orders, while the liquidators, Fisk and David Bridgman from PwC, challenged the point over the $500,000.
In a majority judgment released in March, Justices Christine French and Rhys Harrison dismissed both appeals.
Justice Forrest Miller, in a dissenting judgment, dismissed McIntosh's appeal but said he would have allowed the liquidators' appeal - effectively meaning the Wellington lawyer would have needed to pay back the full $954,000.
Ross Asset Management collapsed in November 2012 leaving some of 1200 clients $115 million out-of-pocket. It was later revealed that director David Ross was running a Ponzi scheme.
He was convicted of fraud and jailed for 10 years and 10 months.
