A top Defense Department official and the federal watchdog charged with overseeing U.S. spending in Afghanistan clashed on Wednesday about a now-defunct Pentagon task force that spent $43 million to build a natural gas station in that country, among many other questionable expenditures.

The Pentagon’s Task Force for Business and Stability Operations (TFSBO), which received more than $800 million from Congress to spend on economic redevelopment in Afghanistan, has come under intense scrutiny on Capitol Hill following a series of reports about wasteful spending.

Related: How Millions of Taxpayer Dollars Were Wasted on Afghan Mining Projects

On Wednesday, the Senate Armed Services Committee Readiness and Management Support subpanel finally had a chance to question John Sopko, the Special Inspector General for Afghanistan Reconstruction (SIGAR), and a top Pentagon official about the task force.

“What happened to the money,” asked subpanel chair Kelly Ayotte (R-NH), who is up for re-election this year. “All of it.”

But rather than reach definitive conclusions about TFSBO, Sopko and Brian McKeon, principal deputy undersecretary of defense for policy, engaged in a two-hour debate about the watchdog’s access to agency files and personnel and the price tag of the gas station that prompted the hearing in the first place.

Related: What's Inside the Pentagon’s $800 Million Afghanistan ‘Slush Fund’?

In a running exchange, McKeon maintained that the $43 million figure was actually determined by an outside contractor whose methodology, the Pentagon has since concluded, was “flawed” because it didn’t accurately account for labor and overhead costs.

He put the real price for the station “well under $10 million” – which is still extraordinary high for a project that should have cost $500,000.

Sopko countered with the fact that the Pentagon hadn’t disclosed the involvement of an outside firm when his office published its report in October.

Related: Pentagon Posh: U.S. Spent $150 Million on Luxury Villas in Afghanistan

“It was the best evidence that we had at the time,” he said. “We don’t make numbers up.”

Sopko also noted that on Tuesday his staff received a 100-gigabyte hard drive of data from the Pentagon about the task force’s work but it’s so “substantially inadequate” that a forensic team is reviewing it to determine if it’s been manipulated.

Ayotte and others also grilled McKeon about $150 million TFBSO members spent on private villas and security for themselves, ostensibly to conduct business in the war-torn country.

McKeon said he wasn’t sure if the arrangement did, in fact, secure any contracts for U.S. businesses.

At one point Ayotte asked if any of the hundreds of millions spent by the task force actually amounted to anything.

“That’s the big question, senator, and it’s the right one to ask,” he replied, adding it’s “too early to say,” despite the task force’s record of “mixed results.

Sen. Claire McCaskill (D-MO), a major SIGAR booster, chided the Pentagon official for the department’s “brilliant” decisions and warned that contesting the price tag for the natural gas station only makes lawmakers more suspicious of the agency.

At one point, McKeon admitted he is “personally” skeptical that the Defense Department is the natural home for development missions, something lawmakers seemed to agree on with him as the proceedings chugged along.

Sopko said his office wants to account for the millions of dollars dispersed by the task force but might not be able to because he lack subpoena power.

“That would be very helpful,” he told the panel.

Indeed, Wednesday’s sessions also raised more questions about TFBSO’s activities, including members traveling to India to try to foster Afghanistan’s jewelry industry; an ice cream initiative run out of the task force’s villas; a trip to a carpet expos in Europe to drum up interest in Afghan carpets; and the possible importation of a large number of goats from Italy as part of a cashmere wool initiative.

Sopko said underlying problems with the task force, and its legacy, amounts to “poor planning, poor management and poor coordination.”