The Internal Revenue Service, which is already in hot water for concealing its abuse of conservative nonprofits from Congress, may also have lowballed a U.S. senator who asked last year how much of the taxpayers’ money it was spending on lavish parties for staffers.

According to a report [pdf] issued Friday by the Treasury Inspector General for Tax Administration (TIGTA), IRS officials spent more than $49 million on more than 200 conferences for employees between 2010 and 2012.

But last year, when Republican Sen. Tom Coburn asked then-Secretary of the Treasury Tim Geithner how much IRS had spent on conferences during that exact period, Treasury replied that the federal tax collector had spent only $500,000 on just five conferences.

That’s a fraction of what the IRS spent on just one $4.1 million conference in Anaheim, California, during which attendees were treated to a $17,000 keynote speaker who performance-painted portraits of celebrities. According to the TIGTA report, IRS festivities also included parody videos of “Star Trek” and an employee dance routine. Faris Fink, the commissioner of Small Business and Self-Employed division, who portrayed Spock in the “Star Trek” parody, reportedly stayed at the two-bedroom presidential suite at the Anaheim Hilton.

“On April 16, 2012, I wrote to then-Treasury Secretary Timothy Geithner requesting a full listing of all conferences attended by department employees during fiscal years 2010, 2011, and 2012, including the title, location, date, and number of employees who attended,” Coburn’s letter reads.  “Additionally, the letter requested a full listing of conferences that received financial support from the agency, including those where it was the primary host, a sponsor, or provided some other support.

“In response, Treasury provided a list titled ‘Treasury Departmental Offices Overnight Conferences (1/1/2005 – 6/1/2012) Attended by 50 or more Treasury Staff.’ On that list, there were only five conferences, with a total cost under $500,000.  Only one of these conferences took place during the time period requested in the letter. None were related to the IRS or its employees,” Coburn writes.

That the IRS appears to have been withholding information from another legislative probe recalls the widening scandal around the agency’s targeting of conservative nonprofits. During testimony in July 2012, then-commissioner Steven Miller told the House Ways and Means Committee that the IRS was not singling out conservatives, though he had known of the policy since at least March of that year and conservative nonprofits had been complaining for much longer.

The May 2012 letter to Coburn, claiming the half-million-dollar figure, came from Alastair M. Fitzpayne, Treasury’s Assistant Secretary for Legislative Affairs, who asserted that the agency was making efforts to reduce its travel and conference costs.

“As an agency responsible for managing the finances of the federal government,” Fitzpayne wrote, “we are keenly aware of the need to safeguard limited taxpayer resources.”