TOPEKA — A legislative audit released Monday contradicted information the Kansas Department of Corrections gave lawmakers about the least expensive way to replace its oldest and largest prison with the agency already facing scrutiny over unrest at another maximum-security facility.

The audit said the cheapest route for financing a new prison in Lansing in the Kansas City area is for the state to issue bonds. The department wants to replace the existing prison because parts of it date to the 1860s and it has concluded that even newer buildings aren’t as safe and efficient as a modern prison.

The department has told legislators that a new prison could run safely with fewer employees and the least expensive option was to have the company building it lease to the state for up to 40 years before the state took ownership. It said annual savings in operating costs would more than cover lease payments.

Lawmakers authorized both a lease-purchase deal and $155 million in bonds to finance the new prison. The audit said the 20-year cost of bonds would between $178 million and $193 million, while a 20-year lease purchase agreement would cost $206 million. The department had said a lease-purchase deal would be $13 million cheaper over 20 years.

Auditors said the department’s estimates “were missing key variables and used inconsistent assumptions that tended to favor a lease-purchase option.”

“They wanted us to choose that option, or allow them choose that option, so the fact that they fudged the numbers doesn’t surprise me,” said state Sen. Laura Kelly, a Topeka Democrat and a member of the joint legislative committee that directs auditors’ work.

The department did not formally dispute the audit’s findings in its response, and spokesman Todd Fertig said the agency welcomed a review. But Fertig added that the true costs of the Lansing project won’t be known until proposals from bidders are reviewed.

“All along, we’ve been open to either option,” Fertig said. “We never tried to weigh one in favor of the other.”

The audit committee’s chairman, Republican Rep. John Barker, of Abilene, dismissed concerns about the different numbers.

“Good people always can differ,” Barker said.

While lawmakers authorized the project, they mandated multiple additional reviews. The department hopes to have a final construction contract this fall.

Meanwhile, Kelly is pushing to have legislative auditors review multiple inmate disturbances at the El Dorado Correctional Facility, about 30 miles east of Wichita. The audit committee will consider her request in October; if the review goes forward, a report would be ready for lawmakers early next year.

The department has confirmed incidents May 8, June 24 and June 29 in which groups of inmates temporarily refused to return to their cells.

In the third incident, Corrections Secretary Joe Norwood confirmed, inmates smashed a window in the gym and temporarily gained access to an office there. He confirmed the May 8 and June 24 incidents after they were reported by The Associated Press, which interviewed three corrections employees who spoke anonymously because they feared reprisals.

The employees described the incidents as more serious than the department did. Kelly said she wants auditors to determine what actually happened.

“We need some more transparency in the Department of Corrections,” she said.

On Friday, two separate inmate-on-inmate altercations resulted in a prisoner from each fight being taken to an outside hospital, according to the department. However, the department said it found no evidence of a significant disturbance.

Fertig said the department does not object to a legislative review. “We never have had a lack of transparency,” he added.

Kansas prisons have faced staffing shortages for years because of low pay for uniformed corrections officers, which starts at $13.95 an hour. As of last week, 20 percent of those positions at El Dorado were vacant, and employees were required to work 12-hour shifts.