SEATTLE -- The City Council is asking tough questions about cost overruns with a new billing system.

On Tuesday, Seattle City Light and Seattle Public Utilities Project Managers had to give answers to the Council's questions concerning the system, which will replace the current 15-year-old version. Council member Kshama Sawant says her latest data shows the project is well behind schedule and $40 million dollars over budget.

An independent consultant concluded there was a lack of oversight, but Council members seem concerned as well, about the lack of communication about the problems from the Mayor's Office.

City Light says based on current math, the problems will cost the average residential customer 11 cents per month. Based on their current estimate, the overruns will cost the average residential customer 50 cents per month, says SPU. Both utilities say that number could go down if they make cuts to other capital investment projects.