In an e-mail, a CGI-AMS spokeswoman said that "the system was designed according to the original specifications. We are committed to working with the DOR to resolve outstanding issues" without charge.

The ITS was designed to automatically process sales and use taxes and to determine how much revenue is distributed to Wisconsin's 58 counties and two professional sports districts.

Since the installation, the system has been plagued by software defects that caused calculation and programming errors along with processing backlogs.

According to a report issued last month by the state legislature's audit bureau, the system has underpaid several counties by $9.1 million combined and overpaid others by $8.8 million. Most of those discrepancies have been settled.

The legislature's report pointed to a lack of familiarity with the ITS processes and forms by the state's retailers and the DOR's own staff for some of the problems. In addition, the report said that incomplete information was entered into the system, causing it to misread tax obligations and miscalculate retailer discounting computations.