"I don't know of any correlation (between) the time of service and the amount of overtime," Ashley said, adding that a senior officer's overtime pay will be higher because his or her base pay is higher. Ashley said much of the overtime paid to officers is required to keep the department at minimum manning levels.

"Our ultimate goal is to protect the citizens of Tulsa," Ashley said. "We have a minimum manpower level for officers on each shift on each side of town, and we cannot dip below that."

Some police work, like investigating a late-night murder, doesn't fit neatly into a 9-to-5 schedule and often requires extra hours, Ashley said. He, like Ballenger, noted that a lot of overtime pay that officers receive is for working special events. City finance officials on Friday estimated the reimbursement to be less than 10 percent.

Ashley said having more officers would likely help reduce the need for overtime.

"We would love to have more officers," he said, but added that the tough economy makes that difficult.

His boss, Deputy Chief Daryl Webster, told city councilors last year that adding more officers would actually increase the need for overtime.