Farance also said next February's four-day meeting will be too short to address the hundreds of comments and other complaints about Open XML.
Robertson said such accusations are overblown.
"Open XML is a very strong specification, created in a year-long period within Ecma through attentive work by very well-respected companies and entities," Robertson said. "Can it be improved? Yes. Ecma will respond to every single comment, as it should."
A surprise change of attitude
INCITS vote is a bit of a surprise: until last Thursday, Open XML, which is the native document format in Office 2007, had failed at multiple junctures to garner sufficient support within the group.
In mid-July, the V1 technical committee advising the executive board of INCITS failed to approve Open XML, which was put onto an ISO fast track approval process in March.
Earlier this month, the executive board of INCITS failed to pass a resolution in favor of Open XML.
But at last Thursday's meeting, four members swung from their prior 'no' votes to support Open XML. Those four were GS1, a non-profit group that is best known for overseeing the Universal Product Code (UPC) stamped on retail products, printer maker Lexmark, NIST, and the Department of Defense.
There have been some claims that Microsoft has tried to influence the heads of these government agencies to support Open XML, with top executives including Chairman Bill Gates and CEO Steve Ballmer allegedly making calls themselves.
Robertson admitted that Microsoft has lobbied federal officials. But it's not the only one, he says.
"Did we talk to these three government entities? Yes, as did the people who are trying to block Open XML," he said. "The government made it clear that the decision they had to make was one that was fully-informed. Everything we said and did was simply to help inform their decision."
Robertson said that "Gates didn't engage in" these calls. He declined to comment on whether Ballmer was involved.